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Q1.The gas used in discharge tubes for optical  decoration and advertising is- 
optical decoration and which gas discharge tubes for the ad is 
(a) Carbon dioxide / carbon dioxide 
(b) Ammonia / ammonia 
(c) Sulphur dioxide / Sulfur dioxide 
(d) Neon / Neon
Show Answer
Ans. (D) 
Sol. The neon gas is used in discharge lamps, tubes and in fluorescent bulbs.

Q2. The formation of glittering colours in thin foam  of soap is the result of which of the following phenomenon- 
formation of bright colors in thin foam soap is a result of the event of the following 
(a) Reflection and interference / reflection and interference 
(b ) Total refraction and dispersion / total refraction and dispersion  
(c) Diffraction and dispersion / dissection and dispersion 
(d) Polarization and interference / polarization and interference
Show Answer
Ans. (A) 
Sol. A soap bubble is a very thin sheet of water sandwiched between two layers of soap molecules. Light is reflected from both the inner and outer surface of the soap bubble. The resulting colors are a combination of the colors that do not lead under destructive interference and their degrees of constructive interference. Blue-green colors dominate in thicker films and yellow hues in thinner films
Q3 Total internal reflection can be:  
Total internal reflection can occur when light is traveling from ________: 
(a) Diamond to glass / diamond to glass 
(b) Water to glass / water to glass  
(c) Air to water / Water by air 
(d) Air to glass / Air from glass
Show Answer
Ans. (A) 
Sol. Total internal reflection takes place when a ray of light is travelling from denser to thinner medium and angle of incidence is greater than critical angle, the ray is completely reflected from the surface and meet one another as if the surface is a mirror. So according to options, the situation of option (a) is correct where total internal reflection takes place, it is because diamond is denser than glass 

Q4. Optical fiber works on the principle of: Optical fiber works on the principle of  
(a) Total internal reflection / total internal reflection 
(b) Refraction / refraction 
(c) Scattering / scattering 
(d) Interference / Interference
Show Answer
Ans. (A) 
Sol. The optical fiber is a very hand-loaded glass or plastic cable for transmitting light from one point to another. They work on the theory of total internal reflection. There is no loss of signal through an optical fiber 

Q5. In fibre-optics communication, the signal  travel in the form of- 
fiber optics communications, travels as whom Signal -  
(A) Lightwave / light wave 
(b) Radio wave / radio wave 
(c) Microwave / microwave 
( d) Electric wave / electric wave
Show Answer
Ans. (A) 
Sol. Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber.

Q6. "Endoscope" is used by doctors 
to examine the inside of the patient's stomach,  "Endoscope" is used, what principle does it work on? 
Reflection of light / Reflection of light 
(b) Dispersion of light / Dispersion of light 
(c) Refraction of light / refraction of light 
(d) Total internal reflection of light / Total internal reflection of light
Show Answer
Ans. (D) 
Endoscopes are widely used for the interior of a hollow organ or cavity of the body. They are based on the principle of total reflection within a fiber optic bundle of fibers.

Q7 The reason of mirage is 
the cause of the mirage  
(a) Interference of light / light interference 
(b) Diffraction of light / diffraction of light   
(c) Polarization of light / polarity of light 
(d) Total internal reflection of light / light Total internal reflection
Show Answer
Ans. (D) 
Sol. The mirage is due to the total internal reflection of light at layers of different densities. In Desert areas, the successive upper layer is denser than those below there. A ray of light coming from a distant object, like the top of a tree gets refracted from a denser to a rare medium. Consequently, the refracted rays bends away from the normal until a particular layer, the light is incident ray suffers total internal reflection and enters the eyes of the observer. It appears as an inverted image of the tree 

Q8. The diamond appears lustrous because of: The diamond appears to  
be shiny because: 
(a) Interference of light / light interference 
(b) Dispersion / deflection  
(c) Total Internal Reflection / total internal reflection  
(d) Scattering / dispersion
Show Answer
Ans. (C) 
Sol. The refractive index of diamond is very high. Diamond achieves brilliance It has been cut or designed in such a way that if light enters in-to, incident light strikes many of the internal surfaces. After many such reflections, the color in the light is separated and hence seen individually. 

Q9. The technique to integrate and mark the image of a three-dimensional object is- The technique for integrating and marking the image of a three-  
dimensional object- 
 (a) Audiography / Audiography 
(b) Lexieography / Sketch 
(c) Photography / Photography 
(d) Holography / Holography
Show Answer
Ans. (D) 
Sol. Holography is a technique that produces a three-dimensional image.

Q10. 'Raman effect' deals with the light rays passing through 
'Raman effect' based on which light rays passing through  
(a) Only fluids / Liquid 
Only (b) Only prisms / Prism only 
(c) Only diamonds / Diamonds only 
(d) All transparent medium / All transparent medium
Show Answer
Ans. (D) 
Sol. Raman effect deals with the light rays passing through all the transparent medium According to this, a beam of light traverses a dust-free transparent sample of a chemical compound, a small fraction of light emerges in the direction of the other than the incident (incoming) beam .

Q11. A CD (Compact Disc) audio player uses a: What does  
a CD (compact disc) audio player use: 
 (a) Quartz / quartz 
(b) Titanium needle / titanium needle 
(c) Laser beam / laser beam 
(d) Barium titanic ceramic / bariat tetanic ceramic
Show Answer
Ans. (C) 
Sol. The lens used in CD player emit ultraviolet laser beams

Q12. Television signals can not be received beyond a certain distance because: Television signals can not be  
obtained over a certain distance because 
 (a) Signals are weak / signal is weak 
(b) Antenna is weak / antenna is weak 
(c) Air absorbs Signals / air absorbs signal 
(d) The surface of the earth is curved / Earth's surface is curved
Show Answer
Ans. (D) 
Sol. Television signals can not be received from the surface of the earth is curved, due to the signals moves without the hitting of the earth's surface. 

Q13. The technology used to transmit audio signals in television broadcasts is: 
 Which technology is used to transmit audio signal in television broadcast  -  
 (a) Amplitude Modulation / Dimension Modulation 
(b) Frequency Modulation / Frequency Modulation 
(c) Pulse Code Modulation / Pulse Code Modulation 
(d) Time Division Multiplexing / Time Division Multiplexing
Show Answer
Ans. (B) 
Sol. Frequency modulation is used to transmit audio signals in television broadcasts. Frequency Modulation is the process in which the frequency of the carrier signal is varied by the modulating signal while the amplitude remains constant 

Q14. The image formed on Retina is: The  
reflection created on the retina: 
(a) Larger than object and Inverted / Larger 
than the object but inverted (b) Smaller than object but straight / Small but straightforward object 
(c) Smaller than object and Inverted / Object Small but inverted 
(d) Equal to object but straight / Object but equal to
Show Answer
Ans. (C) 
Sol. The inverted image formed on the retina is the brain by the optic nerve in the form of electrical signals.

People suffering from mayopia are advised to use ________ 
 (a) convex lens / convex lens 
 (b) concave lens / concave lens 
 (c) plano-convex lens / plano-convex lens 
(d) plano-concave lens / plano-concave lens
Show Answer
Ans. (B) 
Sol. Myopia is the term used to define being shortsighted. It can be corrected by using concave lens.

Q1. A 100 watt electric bulb was used for 10 hours. What is the cost of electricity consumed, if the consumption cost is Rs. 5 per unit? 
A 100-watt electric bulb is used for 10 hours. If the cost of consumption is Rs 5 per unit then what will be the cost of electricity consumption? 
(a) Rs. 5/5 
(b) Rs. Rs.10 / 10 
(c) Rs. 25/25 
(d) Rs. 50/50
Show Answer
Ans. (A) 
Sol. Energy Consumption of 100 watt electric bulb which was used for 10 hours = 100 × 10 
= 1000 watt hour 
= 1 kilo watt hour 
= 1 unit. 
According to question the cost of 1 unit of electricity = Rs. 5

Q2. If a bulb of 100 watt burns for 10 hours, the expenditure of electricity will be- 
If the 100-watt bulb burns for 10 hours,  what will be the cost of electricity? 
(a) 0-1 unit 
(b) 1 unit 
(c) 10 unit 
(d) 100 units
Show Answer
Ans. (B) 
Sol. Energy Consumption of 100 watt electric bulb which was used for 10 hours = 100 × 10 
= 1000 watt hour 
= 1 kilo watt hour 
= 1 unit. 
According to question the cost of 1 unit of electricity = Rs. 5
Q3 The value of 1 kilowatt hour is 1 kilowatt hour  
(a) 3.6 × 106 j 
(b) 3.6 × (10) ^ 3 j 
(c) (10) ^ 3 j 
(d) (10) ^ 5 J
Show Answer
Ans. (A) 
Sol. 1 Kilowatt hour = 1 (kilowatt) (1 hour) 
= (1000 joule / sec) (3600 sec.) 
= 36 × (10) ^ 5 Joule 
= 3.6 × (10) ^ 6 Joule 
Thus, option (a) is correct.

Q4. An electric bulb of 100 watt was used for 4 hours. 
An electric bulb of 100 watts is used  for 4 hours. The energy used is the unit of energy:
(a) 400 (b) 25 (c) 4 (d) 0.4

Show Answer
Ans. (D) 
Sol. The electric energy consumed = 100 watt × 4 hour 
= 400 watt hour 
= 400/1000 watt hour 
= 0.4 kilowatt hour 
= 0.4 unit. 

Q5. Electricity consumption is based on the measurement of  
electricity - 
1. Watt / Watt 
2. Voltage / Voltage 
3. Ohm / Ohm 
4. Ampere / Ampere 
Select your answer of the following codes-  
following codes Select your answer:
(a) Only 1 / only 1 
(b) 1 and 
2/1 and 2 (c) 2 and 
3/2 and 3 (d) 1 and 4/1 and 4
Show Answer
Ans. (A) 
Sol. Electricity bill is based on the measurement of kilowatt / hour (kw / h). The kilowatt hour is a unit of energy, equal to 1000 watt.

Q6. How many units of electricity will be consumed if you use a 60-watt electric bulb for 5 hours a day for 30 days? 
If you use 5 hours 60 watt bulbs for 30 days per day, then how many units will power consumption? 
(a) 12 
(b) 9 
(c) 6 
(d) 3
Show Answer
Number of unit = kilowatt hour = watt x hour/1000 

= (60×30×5)/1000=9 unit.

Of the two bulbs in a house, one glows In this context 

One of the two bulbs in a house shines more than the other. Which of the following statements is true in this context? 
(a) The brightness does not depend on the resistance / Brightness is not dependent on resistance 
(b) Both the bulbs have same the resistance. / Both bulbs have the same resistance 
(c) The bright bulb has greater resistance. There is more resistance in light bulb. 
(d) The dim bulb has greater resistance. There is more resistance in light / low burning bulb
Show Answer
Ans. (D) 
Sol. The bulb 
Power (P) = Voltage (V) × Current (I) 
It is known that = V = I × Resistance (R) 
P = V ^ 2 / R; Pα1 / R Thus, the bulb of high resistance decays low energy and will generate dim light. 

Q8. Of the two bulbs in a house, one glows Which of the two is a big resistance? 
One of the two bulbs in a house shines more than the other. The more resistance in which the bulb:
(A) The Dim Bulb / low burning bulb 
(b) The brighter bulb / more burning bulb 
is (c) Both have the same resistance / similar resistance in both 
(d) The brightness Does depend on the resistance / glow resistance
Show Answer
Ans. (A) 
Sol. A bulb grows when it gets more power. 
Power (P) = voltage (V) × Current (I) 
As we know, V = I × Resistance (R) 
P = V ^ 2 / R; Pα1 / R 
So as described above, larger resistance bulb will be dimmer .

Q9. A dynamo, which is  
called General Electricity, how it works:
(a) Source of ions / source of ions 
(b) Source of electric charge / source of electricity charge 
( c) Converter of energy / converter of energy 
(d) Source of electrons / source of electrons
Show Answer
Ans. (C) 
Sol. A dynamo, which is also known as an electricity generator It is basically a device which converts into mechanical rotation in electric current according to Faraday's law.

Q10. Dynamo is a machine which is used for- Dynamo is a machine used 
for which of the following:
(a) Conversion of high voltage to low voltage / low voltage conversion in voltage 
(b) Conversion of electric energy to mechanical energy / conversion of electrical energy into mechanical energy 
(c) Conversion of mechanical energy to electrical energy / conversion of mechanical energy into electrical energy 
(d) Conversion of low voltage to high voltage / low voltage conversion in high voltage
Show Answer
Ans. (C) 
Sol. A dynamo is a device that converts into electrical energy due to electromagnetic induction.

Q11. Electric motors  
running low voltage are burned because:
(a) They draw more current which is proportional to the voltage. / They attract 
more current which is proportional to the voltage (b) They draw more current which is inversely proportional to the square root of the voltage. / They attract more current which is proportional to the square root of the voltage 
(c) They draw heat proportional to the proportional heat of v ^ 2 / v v ^ 2 
(d) Low voltage sets in electrical discharge. / Low voltage sets are in electrical discharges
Show Answer
Ans. (A) Sol. Electric motors operating at low voltages tend to burn out because they are more current which is proportional to the voltage. 

Q12. A device which converts chemical energy into electrical energy is called- 
a device that converts chemical energy into electrical energy is  called
a. Battery / battery 
(b) motor / motor 
(c) generator / generator 
(d) moving coil meter / moving coil meter
Show Answer
Ans. (A) 
Sol. An electrical battery is a device consisting of two or more electrochemical cell that converts the stored energy into electrical energy. There are different types of batteries but all are three components; a positive electrode, negative electrode, and electrolyte.

Q13. Turbines and Dynamos are used to convert which energy to electrical energy? 
Turbine and dynamos are used to convert which energy into electrical energy? 
(a) Chemical energy / chemical energy 
(b) Solar energy / solar energy 
(c) Mechanical energy / mechanical energy 
(d) Magnetic energy / magnetic energy
Show Answer
Ans. (C) 
Sol. A dynamo is an electricity generator that produces a current current use. It converts into

Q14. When electrical energy is converted into motion  
(a) There is no heat loss / no heat loss 
(b) Heat loss is 50 percent / 50 percent heat loss 
(c) Heat loss is 30% / 30% heat loss 
(d) Heat loss is 80% / 80% heat loss
Show Answer
Ans. (A) 
Sol. When there is no heat loss

Q15. A device which converts electrical energy into mechanical energy is- 
a device that converts electrical energy into mechanical energy 
(a) Dynamo / dynamo 
(b) Transformer / Transformer 
(c) Electric motor / electric motor 
(d) Inductor / Inductor
Show Answer
Ans. (C) 
Sol. Electric motor is a device which can be converted into mechanical energy. Electric motors include rotating coils of wire which are driven by the magnetic force exerted by a magnetic field or an electric current.

Q1. I-Water, II-Steel, III-Nitrogen- Arrange the speed of sound in the  
following medium i-water, II-steel, III-nitrogen-in ascending order. 
(a) III, II, I 
(b) III, I, II 
(c) I, III, II 
(d) II, I, III
Show Answer
Ans. (B)
Sol. The speed of sound is different The speed of sound is maximum in solids while minimum in gas. The speed of sound in air at normal temperature and pressure is 322m / s. The speed of sound depends on the way it is travelling. The medium which has high density, the sound will travel faster in that medium.

Q2. In which medium the speed of sound is maximum at a temperature of around 20 ° C? 
In which medium does the speed of the sound be maximized at a maximum temperature of 20 degree Celsius? 
(a) Air / Air 
(b) Granite / Granite 
(c) Water / Water 
(d) Iron / Iron
Show Answer
Ans. (D)
Sol. The speed of sound depends on the elasticity and density of the medium through which it is travelling. Greater the elasticity and lower the density, the sound travels faster in that medium. At temperature of 20 ° C, the speed of sound is maximum in iron.

Q3 Sound waves-  
Sound waves- 
(a) Can travel in vacuum / vacuum 
(b) Can travel only in solids / can travel only in concrete 
(c) Can travel only in gases. 
Can travel only in gases (d) Can travel both in solid and gaseous medium. / Can travel in both concrete and gaseous medium.
Show Answer

Q4. The walls of the hall, built for music concerts 
should-be made for the walls of the hall,  music concerts-
(a) Amplify sound / enhanced sound 
(b) Transmit sound / voice communication 
(c) Reflect sound / reflective sound 
(d) Absorb sound / absorption sound
Show Answer
Ans. (D)
Sol. The walls of the hall Most of the solid walls If the walls of concert hall reflects the sound, then audiences hear the echo sound. So to avoid this

Q5. To hear a clear echo, the reflecting surface and the observer should be- To have 
a clear echo / resonance , the minimum distance between the reflected surface and the observer must be- 
(a) 165 feet / 165 feet 
(b) 165 meters / 165 meters 
(c) 16.5 feet 16.5 feet 
(d) 16.5 meters / 16.5 meters
Show Answer
Ans. (D)
Sol. The repetition of sound produced due to the reflection from a large surface like wall, hill or mountain is called echo. Think of an obstacle The sound travel of the observer and the observer Let d be the distance between the observer and the obstacle, v is the sound velocity and t is the time taken by the sound to and fro motion, then velocity of the sound is given by 
v = 2d / t velocity 
of sound is given By, V = 2d / t 
Where t = time taken by the sound for to and fro motion 
Substituting t = 1/10 sec, it is minimum time required to differentiate between two sounds 
V = velocity of sound = 330 m / sec 
at 20 ° C 
then d = Vt / 2 = 1/2 [330 × (1/10) ]
= 16.5 m

Q6. The velocity of sound in air is approximately -  
at 0 ° C in the air, the speed of sound is approximately ________. 
(a) 10 km / sec / 10 km / sec 
(b) 10 mile / min / 10 mile / min 
(c) 330 m / sec / 330m / sec 
(d) 3 × 1010 / sec. / 3 × 1010 / sec
Show Answer
Ans. (C)
The speed of sound in air is approximately 331.5 m / s at 0 ° C or around 1200 km per hour. The speed of sound through air is approximately 343 m / s at normal room temperature, which is at 20 ° C.

Q7 Two astronauts can not hear each other on the moon's surface, because - 
two astronauts can not hear each other on the surface of the moon  , because-
(a) Their ears have stopped working on the moon / their ears stop working on the moon to give 
(b) No atmosphere on the moon / no atmosphere on the Moon 
(c) they wear special space suits on the moon / they wear special space suits on the Moon 
(d) the sound travels much more slowly on moon / Moon But the sound travels very slowly
Show Answer
Ans. (B)
Sol. In order for sound to propagate from one place to another, it needs a medium or a fluid to move through. The air on the earth is allowed to move from one point to another. However, there is vacuum on surface of moon Thus, there is no sound on the moon 

Q8. Consider the following statements:  
Consider the following statements: 
Lk A Flute Of Smaller Length Produces Waves Of Lower Frequency K / A short length flute produces low frequency waves. 
2. Sound travels in rocks in the form of longitudinal elastic waves only. / Sound travels in rocks only as longitudinal elastic waves. 
Which of the statements given is up / is correct? 
Which of the statements above is correct? 
(a) 1 only / only 1 
(b) 2 only / only 2 
(c) both 1 and 
2/1 and 2 (d) Neither 1 nor 2 / nor 1 nor 2
Show Answer
Ans. (B)
Sol. A flute of long length produces the waves of high wavelength (λ) and lower frequency (v), thus a flute of small length produces waves of higher frequency (v) and lower wavelength (λ). So statement 1 is not correct Sound is a longitudinal wave. Transmission of sound Thus, sound travels in rocks, in the form of referential wave. Longitudinal waves are the waves in the displacement of the medium is the same direction as or the opposite direction to the direction of travel of the wave. Thus statement 2 is correct.

Q9. Consider the following statements about ultrasonic waves:  
Consider the following statements about the ultrasonic waves to: 
Lk They Can Destroy Insects / they destroy insects. 
2. They can clean clothes by removing the dust. 
3. They can be used to treat disease. 
4. They can control automatic doors / they control automatic doors. 
Of the above statements    
(a) 1 and 2 are correct / 1 and 2 is true 
(b) 3 and 4 are correct / 3 and 4 is true 
(c) 1, 2 and 3 are correct / 1, 2 and 3 is true 
(d) All are correct / all is true
Show Answer
Ans. (D)
Sol. Sound waves are longitudinal-mechanical wave. Sound waves are divided into three categories that cover different frequency range; Audible wave (20htz- 20,000htz), Infrasonic waves (<20Htz) and Ultrasonic waves (> 20,000htz). Detecting of aircraft and submarine, determination of depth of sea etc.

Q10. Ultrasonics are sound waves of frequency The frequency of  
ultrasonic sound waves are _________. 
(a) Greater than 20,000 Hz / 20,000 Hz 
(b) Less than 10,000 Hz / 10,000 Hz 
(c) Equal to 1000 Hz / 1000 Hz 
(d) None of these None of these
Show Answer
Ans. (A)
Sol. Sound waves are longitudinal-mechanical wave. Sound waves are divided into three categories that cover different frequency range; Audible wave (20htz- 20,000htz), Infrasonic waves (<20Htz) and Ultrasonic waves (> 20,000htz). Detecting of aircraft and submarine, determination of depth of sea etc.

Q11. A biotechnique in which ultrasonic sound used is used - 
biotechnique in which ultrasonic sound is   used - 
(a) Sonography / Sonography 
(b) ECG / ECG 
(c) EEG / E.E.G. 
(d) X-ray / X-ray
Show Answer
Ans. (A)
Sol. Sonography or ultrasonography is an important means of clinical diagnosis. It is a diagnostic imaging technique based on the application of ultrasound. It is widely used in the field of medical science. It is used as a variety of information about the health of the mother during pregnancy, and the health and development of the embryo or foetus.

Q12. Bats can fly during dark nights and also prey. This is because -  
Bat can fly during dark night and can also be hunted. Because - 
(a) The pupil of their eyes is large / Their pupil of the eyes is big 
(b) Their night vision is very good / their night vision is very good 
(c) Every bird can do this can 
(d) they produce ultrasonic waves and are guided by them./ they are guided by the production of ultrasonic waves and their.
Show Answer
Ans. (D)
Sol. Bats are a fascinating group of animals. They are one of the few mammals that can use ultrasonic voice to navigate. As they fly, make an ultrasonic (shouting) sound The returning echoes give the bats information about anything that is ahead of them, including the speed and size of a insect and which way it is going to go. This system of finding is called echolocation-locating things by their echoes.

Q13. Which one of the following is the supersonic jet? 
Which of the following is the effect of flying supersonic jet?  
(a) Air pollution / Air pollution 
(b) Eye disease / Eye disease 
(c) Depletion in ozone layer / Decrease in ozone layer 
(d) None of these / None of these
Show Answer
Ans. (C)
Sol. A jet engine is a machine for turning fuel into thrust. The thrust is produced by action and reaction also known as the Newton's third law of motion. The force (action) of the exhaust gases pushing backward produces an equal and opposite force called thrust, that powers the vehicle forward. Those jet planes that are able to fly faster than the speed of sound are called supersonic jet planes. Jet engine is responsible for depletion of ozone Flying at stratosphere height, they emits nitrogen oxide which has the potential to destroy significant quantities of ozone in the stratosphere.

Q14. Decibel unit is used to measure- Decibel unit is used  
for measuring -
(a) Light intensity / light intensity 
(b) Sound intensity / sound intensity 
(c) Magnitude of Earthquake / Earthquake intensity 
(d) None of the above / none of the above
Show Answer
Ans. (B)
Sol. 'Decibel' is used to measure

Q15. According to WHO, the safe noise level for a city is- 
According to WHO, the safe voice level for a city is -
(a) 45 db 
(b) 50 db 
(c) 55 db 
(d) 60 db
Show Answer
Ans. (A)
Sol. As per the WHO the safe noise level for a city is 45 decibel (db).

Q1. The working principle of a washing machine is: What is the principle of working in a washing  
(a) Centrifugation / centrifugation 
(b) Dialysis / 
upholstery (c) Reverse Osmosis / Unlike osmosis 
(d) Diffusion / diffusion
Show Answer
Ans. (A)
Sol. The working principle of a washing machine is based on centrifugation force. The term centrifugal force was used to refer to an inertial force or fictitious force, a particle moving on a circular path that has the same magnitude and dimensions as the force that has its circular path on particle but opposite direction in point .

Q2. Which of the following is not a vector quantity? 
Which of these is not a given line (vector quantity)? 
(a) Displacement / Displacement 
(b) Velocity / Velocity 
(c) Force / Force 
(d) Volume / Volume
Show Answer
Ans. (D)
Sol. A Vector is a quantity that is fully described by both magnitude and direction. On the other hand, a quantity is a quantity that is fully described by its magnitude. Thus displacement, velocity and force are the examples of vector quantity.

Q3 Which physical quantity is represented by the ratio of the momentum and the velocity of the body? 
What is the physical quantity represented in proportion to the speed and momentum of the object? 
(a) Velocity / Velocity 
(b) Acceleration / Acceleration 
(c) Mass / mass 
(d) Force / Force
Show Answer
Ans. (C)
Sol. Momentum is a vector quantity that is the product of Mass and the Velocity of an object. 
Momentum = Mass × Velocity 
So,  Mass = Momentum / Velocity

Q4. Force is the product of- 
 force ___ is produced. 
(a) Mass and velocity / mass and velocity 
(b) Mass and acceleration / mass and acceleration 
(c) Weight and velocity / weight and velocity 
(d) Weight and acceleration / weight and acceleration
Show Answer
Ans. (B)
Sol. A force can cause an object with mass its change, which is to move from one place to another. 
Force = Mass × Acceleration = ma 

Q5. If the number representing volume and surface area of ​​a cube are equal, then the length of the edge of the cubicle in the unit of measurement is- 
if the number representing the volume of the cube and the surface area is equal, the measurement In the context of the unit, the length of the side of the cube will be -
(a) 3 
(b) 4 
(c) 5 
(d) 6
Show Answer
Ans. (D)
Sol. Volume of a cube = l ^ 3 (where l is the length of cube's edge) 
Surface area of ​​cube = 6l2 
according to the question, both are equal to one another. So l ^ 3 = 6 l ^ 2 
hence l = 6

Q6. Energy Conservation 
means - Energy conservation  means - 
(a) Generation and destruction of energy / energy production and destruction 
(b) Energy can be made / Energy can be made 
(c) Energy could not be created but destroyed / Energy Can not be made but can be destroyed 
(d) Energy can not be nor destroyed / Energy can neither be made nor can be destroyed
Show Answer
Ans. (D) Energy Conservation refers to the use of energy.

Q7 Kinetic energy equal to Kinetic energy is equal to 
(a) mgh 
(b) mv2 / 2 
(c) mv 
(d) ma
Show Answer
Ans. (B)
Sol. The kinetic energy is the moving objects or mass. The kinetic energy equal to mv2 / 2

Q8. As the train starts moving, the head of the passenger sitting inside leans backward because- 
As soon as the train starts running , the head of the passenger sitting inside  bends backwards -
(a) Inertia of Rest / Stability 
(b) Inertia of motion / motion of motion 
(c) Moment of Inertia / Inertia Tendency 
(d) Conservation of Mass / Stability of the mass
Show Answer
Ans. (A)
Sol. According to the Newton's first law of motion, sometimes referred to as the law of inertia, which states that an object at rest remains in rest and in motion is in motion with same speed and in the same direction unless acted upon by a unbalanced force. When a train starts suddenly, the passenger trains to fall backward This is the lower part of the body which starts in the train. As a result, the upper part tends to fall backward.

Q9. Assertion (A): A man standing on a completely frictionless surface 
Logic (A): A man standing on a completely frictionless surface can push himself while walking. 
Reason (R): If no external force acts on a system, its momentum can not change. 
Reason (R): If an external force does not work on any system, its speed can not change. 
(a) Both A and R are true and R is the correct explanation of A / A and R both true and R is the correct interpretation of A. 
(b) Both A and R are true but R is not a correct explanation of A / A and R is not true interpretation of R, A is true. 
(c) A is true but R is false / A is true but R is false. 
(d) A is false but R is true / A is false but R is true.
Show Answer
Ans. (D)
Sol. Movement is not possible Therefore, the statement (A) is wrong. Momentum is the property that is moving in its mass and motion. Therefore, when there is no external force applied on any moving object, its momentum can not change Therefore, the statement (R) is correct.

Q10. It is difficult to walk on the ice because 
of walking on the road because  :
(a) Ice is harder than the road / road, the snow is rigid. 
(b) Road is harder than the ice / snow, the road is harsh. 
(c) Ice does not give any reaction when we press it with your feet, ice does not respond. 
(d) Ice is a lesser friction than the road There is less friction than ice / snow.
Show Answer
Ans. (D)
Sol. It is very difficult to walk on the ice. The roughness of road's surface gives you much frictional force which enables you to move forward on road.

Q11. Consider the following statement and conclusions. Choose the correct conclusion 
Consider the following statements and findings from them. Select the correct conclusions 
Statement: In starting a loaded cart, one has to push harder than to keep it moving.  
Statement: In starting a weighted car, it has to work harder by taking it forward. 
Conclusion / Conclusion:
(a) The weight of a moving object is less. / The weight of a moving object is low 
(b) The wheels tend to slip initially / The wheels slip initially 
(c) There is less friction once the cart starts moving. / There is less friction after driving 
(d) Practice makes perfect. / Practice Makes Perfect
Show Answer
Ans. (C)
Sol. The static friction that holds an object in place is greater than the kinetic friction that slows down a moving object. In other words, once you start an object moving, the friction decreases from the static friction. You have seen your It can be easy to push, it is easy to push 

Q12. A man jumped at a speed of 5 meters per second from a stationary boat and the boat moved off with the speed of 0.5 meters per second. How many times is the mass of the man? 
A man jumps at a speed of 5 meters per second from a steady boat and the boat runs at speeds of 0.5 meters per second. How much will the mass of the boat be compared to man? 
(a) 5.5 times / times 
(b) 4.5 times / times 
(c) 2.5 times / times 
(d) 10 times / times
Show Answer
Ans. (D)
Sol. Let the mass of the person be M and the mass of the boat is N, then the momentum of boat + momentum of person before Jump = 0 
Then Momentum of both after man's jump = M × 5 - N × 0.5 
⇒ M × 5 - N × 0.5 = 0  (According to the principle of conservation of momentum.) 
∴ N × 0.5 = M × 5 ⇒ N / M = 5 / 0.5 = 10

Q13. A truck, a car, and a motorcycle have equal kinetic energies. If equal, stopping force is applied and they stop after travelling a distance of X, Y and Z respectively, then- 
a truck, a car, and a motorcycle have the same kinetic energy. If equal, the insulation force is applied and it stops after distance travels X, Y and Z, respectively-
(a) X> Y> Z 
(b) X <Y <z 
(c) X = Y = Z 
(d) X ≅4Y≅ 8 Z 
Show Answer
Ans. (C)
Sol. If the objects have equal kinetic energy and if equal stopping force is applied on them, then they will stop at the same distance Therefore X = Y = Z

Q14. An oil tanker is partially filled with oil and movements on a level road with uniform acceleration. The free surface of oil then- 
An oil tanker is partially filled with oil and is carried forward on a flat road with a similar speed. So the free surface of oil-
(a) the remains is horizontal / horizontal 
(b) Is inclined to the horizontal with small depth at the rear end / end at the end with a slight depth in the horizontal 
(c) Is inclined to the horizontal with large depth at the end of the end / end at the horizontal with more depth 
(d) Assumes are parabolic curve / parabolic curve
Show Answer
Ans. (D)
Sol. When an oil tanker is partially filled with a level road with uniform acceleration, the free surface of oil then assumes parabolic curve.

Q15. What is the correct equation for finding the acceleration? 
What is the correct equation to know the acceleration? 
(a) a = (vu) / t 
(b) a = u + vt 
(c) a = (v + u) / t 
(d) a = (v + u) / 2
Show Answer
Ans. (A)
Sol. As we know v = u + at or at = v - u 
∴ a = (vu) / t 
Where, v = ultimate velocity of the particle 
u = initial velocity of the particle 
a = acceleration, t = time

Q1. The Puckle gun was invented by 
who was invented by Buckle gun
(a) JL Beared / J.L. Beard 
(b) G. Brousa / G. Brossa 
(c) Karl Benz / Karl Benz 
(d) James Puckle / James Buckle
Show Answer
Sol. In 1718 an Englishman named James Puckle (1667–1724 AD) invented defence gun what proved to be one of the keys steps in the evolution of mechanical machine guns. That year Puckle, a London solicitor patented what he called the Defence Gun. There is some argument among historians about whether this was the first patent of a manually operated revolving-type machine gun, but the importance of Puckle’s gun is that it certainly represents the most refined design to be found till that time.

Q2. Who invented thermoscope, an early form of thermometer? 
Who was the inventor of thermoscope in the initial form of thermometer? 
(a) Sir Christopher Wren / Sir Christopher Wren 
(b) Charles F. Richter / Charles F. Richter 
(c) Galileo / Galileo 
(d) Beno Gutenberg / Beno Gutenberg
Show Answer
Sol. Thermometer or thermoscope was discovered by famous Italian physicist Galileo in 1609.

Q3 Telescope was invented by:  
Who was the invention of the telescope
(a) Hans Lippershey / laughing shirts 
(b) Gutenberg / Gutenberg 
(c) Edison / Edison 
(d) Graham Bell / Graham Bell
Show Answer
Sol. Telescope was invented by Galileo in 1609.

Q4. The microscope 
Which microscope is used to study? 
(a) Distant objects / Remote objects 
(b) Nearby objects / Nearby objects 
(c) Small objects / Small objects 
(d) Micro and nearby objects / Micro and near objects
Show Answer
Sol. A microscope is an equipment that helps in watching micro and nearby objects which cannot be seen by naked eyes.

Q5. Which is the biggest nutrino telescope of the world? 
Which is the world's largest neutrinos binoculars
(a) Galileo / Galileo 
(b) Ice Cube / Ice cube 
(c) Discovery / Discovery 
(d) Challenger / Challenger
Show Answer
Sol. The Ice Cube telescope which was built in December, 2010 is the biggest neutrino telescope of the world. It was designed by the University of Wisconsin.

Q6. Match the following:  
Match the following: 
Ak Typewriter / typewriter  1. Davy / Dewey 
B. X-ray / X-ray          2. Sholes / Scholes 
C. Radio /  Radio          3. Roentgen / Roentgen 
D. Safety Lamp / Safety Lamp  Marconi /  Marconi 
Code / Code:  
(a) 2          3 
(b) 1 
(c) 3          4 
(d) 4  3
Show Answer
Sol. The typewriter was invented by Sholes in 1868. X-ray was invented by Wilhelm Roentgen in 1895, Radio was invented by Guglielmo Marconi in 1901. Safety lamp was invented by Humphry Davy in 1815. 

Q7 Wilhelm Roentgen invented- 
Whilham Roortgen invented  whom-
(a) Radio / Radio 
(b) X-Ray Machine / X-ray Machine 
(c) Electric Bulb / Electric Bulb 
(d) Electric Motor / Electric Motor
Show Answer
Sol. The typewriter was invented by Sholes in 1868. X-ray was invented by Wilhelm Roentgen in 1895, Radio was invented by Guglielmo Marconi in 1901. Safety lamp was invented by Humphry Davy in 1815.

Q8. Who among the following scientists shared the Nobel Prize in Physics with his son? 
Which of the following scientists shared Nobel Prize in physics with his son? 
(a) Max Plank / Max Planck 
(b) Albert Einstein / Albert Einstein 
(c) William Henry Bragg / William Henry Bragg 
(d) Enrico Fermi / Enrico Firmi
Show Answer
Sol. British physicist and chemist Sir William Henry Bragg shared a noble prize in physics with his son William Lawrence Bragg in 1915. With help of his son, he developed x-ray spectrometer for the analysis of crystal structure by mean of x-rays.

Q9. Who invented the BALLPOINT PEN? 
Who invented the ballpoint pen? 
(a) Biro Brothers / Biro Brothers 
(b) Waterman Brothers / Waterman Brothers 
(c) Bicc Brothers / Bikk Brothers 
(d) Write Brothers / Wright Brother
Show Answer
Sol. The Hungarian brothers, Laszlo and George Biro, made the first ball point pen in 1894. It followed the first workable fountain pen which was invented by L.E. Waterman in 1884.

Q10. Which scientist discovered the radioactive element? 
Which scientist discovered the radioactive element? 
(a) Isaac Newton / Isaac Newton 
(b) Albert Einstein / Albert Einstein 
(c) Benjamin Franklin / Benjamin Franklin 
(d) Marie Curie / Mary Kuria
Show Answer
Sol. Marie Skłodowska Curie was a Polish and naturalized-French physicist and chemist who conducted pioneering research on radioactivity.

Q11. What is the name of the CalTech seismologist who used to measure the magnitude of earthquakes? 
What is the name of the Caltech Earthquake Specialist that invented the scale used to measure the magnitude of an earthquake? 
(a) Charles Richter / Charles Richter 
(b) Hiram Walker / Herman Walker 
(c) Giuseppe Mercalli / Jiecepe Mercalli 
(d) Joshua Rumble / Joshua Rumble
Show Answer
Sol. Charles Richter is most famous as the creator of the Richter magnitude scale. 

Q12. Who discovered electric bulb? 
Who discovered the electric bulb? 
(a) Thomas Edison / Thomas Edison 
(b) Alexander Graham Bell / Alexander Graham Bell 
(c) William Cooke / William Cook 
(d) Terry Addison / Terry Edison
Show Answer
Sol. American scientist Thomas Alva Edison is the inventor of the electric bulb.

Q13. What Enrico Fermi invented? 
Who invented Enrique Fermi? 
(a) X ray machine / X-ray machine 
(b) Betatron / bettron 
(c) Cyclotron / cyclotron 
(d) Nuclear reactor / nuclear reactor
Show Answer
Sol. Enrico Fermi was an Italian-American physicist and the creator of the world's first nuclear reactor.

Q14. Who was the inventor of the fountain pen?  
Who was the inventor of fountain pens? 
(a) Petrache Poenaru / Petrae Ponaru 
(b) Parker / Parker 
(c) Chelpark / Chelpark 
(d) Shaeffers / Sheffers
Show Answer
Sol. The Romanian inventor Petrache Poenaru received a French patent on May 25, 1827, for the invention of the first fountain pen with a barrel made from a large swan quill.

Q15. Who among the following invented the small pox vaccine? 
Which of the following invented the smallpox vaccine? 
(a) Robert Koch / Robert Coach 
(b) Edward Jenner / Edward Jenner 
(c) Robert Hooke / Robert Hook 
(d) Louis Pasteur / Louis Pasteur
Show Answer
Sol. The smallpox vaccine, introduced by Edward Jenner in 1796, was the first successful vaccine to be developed.

Q1. Direction of objects 
The direction of motion is the direction of objects: _
(a) Acceleration / Acceleration 
(b) Mass / mass 
(c) Frictional Force / Friction force      
(d) Velocity / Velocity
Show Answer
Ans. (D) 
Sol. Momentum is a vector quantity that is the product of the mass and the velocity of an object or particle. 

Q2. A drop of water is spherical in shape. This is due to: 
The drop of water is due to  the spherical shape:
(a) Surface tension / surface tension 
(b) Low temperature / low temperature 
(c) Air resistance / air resistance 
(d) Viscosity of water / water quality
Show Answer
Ans. (A) 
Sol. The shape of a drop of rain is constrained by the surface tension, which gives the shape to which the surface area is the minimum for given volume. The spherical shape That's why rain drops acquire spherical shape.

Q3. Total momentum of a system ----, if no external impressed force works on it. 
The total speed of a system ----, if an external affected force does not work on it
(a) increases / increases 
(b) Decreases / decreases 
(c) the remains are constant / constant 
(d) None of the above / none of the above
Show Answer
Ans. (C) 
Sol. Remains constant

Q4. Oil spreads on water surface  
because -
Oil is spread on the surface of water because -  (a) Oil is denser than water / oil is dense compared to water 
(b) Oil is less dense than water / oil is less dense than water 
(c) ) Surface tension of oil is more than water / oil surface 
pressure is higher than water (d) Surface tension of oil is less than water / oil surface tension is less than water
Show Answer
Ans. (D) 
Sol. Oil spreads on water 

Q5. Force acts on an object may change 
can change the force acting on an object
(a) Direction / direction 
(b) Shape / size 
(c) Speed / Speed 
All (d) of above / above all
Show Answer
Ans. (D) 
Sol. Force works on an object may change Direction, Shape and Speed

Q6. Pressure inside a soap bubble is- 
The pressure inside a soap bubble  
(a) More than atmospheric pressure / is greater 
than atmospheric pressure (b) Less than atmospheric pressure / is less than atmospheric pressure 
(c) Equal to atmospheric pressure / Atmospheric pressure is equal to 
(d) Half of atmospheric pressure / half of atmospheric pressure
Show Answer
Ans. (A) 
Sol. Soap bubbles are large when soap dissolved in water The pressure inside a soap bubble is more than atmospheric pressure.

Q7 If two bubbles of sap of different diameter, then what will happen? 
If two different diameter bubbles come in contact with the tube, what will happen? 
(a) The size of both the bubbles will remain same. The size of both bubbles will be the same. 
(b) The small bubble will become small and the big bubble will become bigger. 
(c) The big bubble will grow and the larger bubble will become smaller to get the same shape. 
(d) Both bubbles will burst as soon as they come in contact, both bubbles will explode.
Show Answer
Ans. (B) 
Sol. The excess pressure inside the soap bubble is inversely proportional to the radius of soap bubble ie ρ α 1 / r. When the two bubbles are connected through a tube, the air will flow from the small bubble to bigger bubble due to the fact that small bubble having smaller radius will exert more pressure. So the bigger bubble will grow at the expense of the small one.

Q9. Consider the following statement- Consider the following statement 

If there was no phenomenon of capillarity 
If there is no incidence of capability. 
1. It would be difficult to use kerosene lamp then it would be difficult to use kerosene lam 
2. One would not be able to use a straw to consume a soft drink are not able to 
3. the blotting paper would fail to function / Bloting paper fails to work 
4. the big trees that we see around would not have grown on the earth / we can see the big trees are on earth Do not grow which are of the following statements given above are correct? Which of the statements given above is correct?

(a) 1, 2 and 3 only / only 1, 2 and 3 
(b) 1, 3 and 4 only / only 1, 3 and 4 
(c) 2 and 4 only / only 2 and 4 
(d) 1, 2 , 3 and 4 only / only 1, 2, 3 and 4
Show Answer
Ans. (B) 
Sol. Capillary action is the ability of a liquid to flow in narrow spaces without the help of, or even in opposition to external forces like gravity. Kerosene rises in the capillary action If a person wants to use the soft drink As we know capillary action only in the absence of any external force, so one will not be able to use a straw. Blotting paper also works on the theory of capillary action. It has a large number of pores on its surface which acts like a capillary tube. Nature is a great user The fine roots of trees act as capillary tubes, which provides them useful nutrients and water. 

Q10. In a capillary tube a fluid rises more as compared to water, it is due to: In  
a capillary tube the fluid increases more than water, the reason is

(a) Fluid is more viscous than that of water / liquid water the more viscous than 
(b) temperature of fluid is more than that of water / fluid temperature is higher than that of water 
(c) surface tension of fluid is less than that of water / liquid surface tension than water less 
(d) surface tension of fluid is more than that of water / liquid surface tension than water
Show Answer
Ans. (D) 
Sol. In a capillary tube, liquid rises in proportion with its surface tension. The liquid which gets more height

Q11. When an air bubble 
 comes to the surface at the bottom of the lake , what will happen -
(a) Increase in increased size / size 
(b) Decreased in Size / Size Decrease 
(c) Maintain its size / Maintains its size 
(d) Flatten in a disc like shape / like a flat shape in a disc
Show Answer
Ans. (A) 
Sol. When a air bubble is at the bottom of the lake, it will increase in size. The pressure of the trapped air in the bubble decreases due to decreasing vertical liquid depth.

Q12. While traveling by plane, the  
ink-containing pen's ink starts coming out-
(a) Due to decrease in air pressure / due to lack of air pressure 
(b) Due to increase in air pressure / due to an increase in air pressure 
(c) Due to increase in volume of ink / due to increase in the amount of ink 
(d) Due to excessive load / due to excessive weight
Show Answer
Ans. (A) 
Sol. The fountain pen leak at high altitudes It is called low air pressure. The ink inside the fountain pen has high pressure compared to the low atmospheric pressure outside at high altitude, so ink flows out of the pen.

Q13. In automobile hydraulic brakes work on-the- 
automobile hydraulic brakes work on  which principle? 
(a) Archimedes Principle / Archimedes principle 
(b) Newton's law of motion / motion rule of Newton 
(c) The principle of Bernoulli's Principle / Barnauli 
(d) Pascal's Law / Rule of Pascal
Show Answer
Ans. (D) 
Sol. Hydraulic brakes, hydraulic presses, hydraulic elevators, all works on the theory of Pascal's law, which states that the pressure exerted anywhere in a confined incompressible fluid is transmitted all fluid across all directions such that pressure variations remain the same.

Q14. A sudden fall in barometer reading indicates that the weather will be: A 
sudden drop in barometer readings indicates that the weather will be  _______: 
(a) Stormy weather / stormy weather 
(b) Rainy weather / rainy weather 
(c) Cool dry weather / Temperate weather 
(d) Hot and humid weather / hot and humid weather
Show Answer
Ans. (A) 
Sol. A sudden fall in barometer reading indicates that the weather will be stormy.

Q15. Which of the following is the product of derived from the refining process of petroleum? 
Which of the following is a sub-product derived from the petroleum refining process? 
(a) Petrol / Petrol 
(b) Charcoal / Charcoal 
(c) Coal / Coal 
(d) Asphalt / Sand masala masala
Show Answer
Ans. (D) 
Sol. Asphalt is also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be refined product. The primary use of asphalt is in road construction, where it is used as the glue or binder mixed with aggregate particles to make asphalt concrete. Its other uses are for bituminous waterproofing product, including the production of roofing felt and for sealing flat roofs.

Q1. Cooling by a desert cooler is based on  
which cooling by the desert cooler - 
(a) Hot air replacement / hot air replacement 
(b) Air dehydration / air dehydration 
(c) Evaporative cooling / volatile cooling 
(d) Air rehydration / air rehydration
Show Answer
Sol. The cooling by a desert cooler is based on evaporative cooling. These coolers are also known as swamp coolers. 

Q2. Fish can survive in a frozen lake 
because - Fish can survive in a frozen lake  because - 
(a) Fish is warm blooded animals / Fish are hot-blooded organisms 
(b) Fish hibernate in ice / fish in winter the 
(c) water near the bottom does not freeze the / floor does not freeze to the water 
(d) ice is a good conductor is conductor of of heat / ice heat
Show Answer
Sol. This is because of a phenomenon is known as winter stratification in water bodies. In the winter season, the water at the top layer of water bodies will be ice cold (0°C) and are gradually frozen. But still, the bottom layers will have liquid water and maintain a temperature (4°C) which supports the life there. Thus, fishes and other aquatic animals are saved from the frozen top layer of water.

Q3 Increasing the amount of a substance does not change its amount does not change  
in its ________. 
(a) Volume / Volume 
(b) Weight / Weight 
(c) Mass / mass 
(d) Density / density
Show Answer
Sol. Density of an object depends on its mass and volume. Density can be found by using the equation:
Density = Mass/Volume

Q4. At which temperature is the water? 
At what temperature is the maximum water density? 
(a) 4 ° C 
(b) 0 ° C 
(c) -4 ° C 
(d) -8 ° C
Show Answer
Sol. The mass of any substance while heating remains the same however its volume increases. Thus, its density decreases. But water exhibits an anomalous expansion on cooling and contraction on heating within a specific range of temperature. When water at 0°C is heated, it is observed that it contracts between 0°C to 4°C, i.e. volume decreases and thus density increases. The volume of water is minimum at 4°C. Hence the density of water is maximum at 4°C.

Q5. The maximum density of water is on the maximum density of water is  
(a) 373 Kelvin / 373 Kelvin 
(b) 277 Kelvin / 277 Kelvin 
(c) 273 Kelvin / 273 Kelvin 
(d) 269 Kelvin / 269 Kelvin
Show Answer
Sol. The density of water increases with temperature but volume decreases. At 4°C, the volume of water is low and density is maximum. Conversion of Celsius in Kelvin
K = C + 273
= 4 + 273 = 277
So, the density of water is maximum at 277 K.

Q6. Assertion (A): An iron ball floats on mercury but gets immersed in water. 
Logic (A): An Iron Ball floats on Mercury but drowns in water. Reason (R): The specific gravity of iron is more than that of mercury. Reason (R): The specific gravity of an iron is higher than Mercury.  Code:  Code: (a) Both (A) and (R) are true and (R) is the correct explanation of (A) / (A) and (R) are both true and true of (R), (A) There is an explanation. (b) Both (A) and (R) are true but (R) is not a correct explanation of (A) / (A) and (R) both are true, but (R) is not the correct explanation of (A) ( c) (A) is true but (R) is false / (A) is true but (R) is unreal. (d) (A) is false but (R) is true / (A) is unreal but (R) is true.

Show Answer
Sol. An iron ball floats on mercury but gets immersed in water because the relative density of mercury is greater than the relative density of iron and relative density  of  iron is  greater than the relative density than water. Thus statement (A) is correct but reason (R) is incorrect.

Q7 A needle sinks in water while a ship made of iron floats on it. 
A needle is immersed in water while a vessel made of iron floats on it because-
(a) The edges of the needle is pointed / needle is sharp. 
(b) The ship is flat / ship is flat 
(c) The ship driver, by power flat engine / it runs through a power flat engine 
(d) Specific gravity of the needle is greater than that of water displaced by it / needle The specific gravity of it is more than the water displaced by it.
Show Answer
Sol. Relative density or specific gravity is defined as a ratio of the density of a particular substance with that of water. The relative density of pure water is 1. The substance having the relative density more than 1 will sink in water. The ship is designed in such a way that its effective density (m/v) is less than the density of water, so it floats upon the water. But the density of iron needle is much larger than the water.

Q8. While lifting a bucket of water from a well, we feel that the bucket: While lifting a bucket of water from a well, we feel that the bucket  
(a) Becomes above the surface of water / water above the surface becomes heavy 
(b) becomes lighter above the surface of water / water becomes lighter than the surface 
(c) loses stability on coming out of the water / also lose water coming out stability 
(d) has gained mass on coming out of water / receives mass when coming out of water
Show Answer
Sol. According to the Archimedes’s principle of flotation, object appears to be heavier in the air than inside the water or they appear to be less heavy in the water. It is because water exerts an upward force on the objects immersed in it. This reduction is equal to the weight of the fluid that body displaces.

Q9. Cooling is done by- 
cooling is done by- 
(a) Flow of water / water flow 
(b) Release of compressed gas / Prevention of compressed gas 
(c) Cooking gas / gas making 
d) Melting the solid Melting / concrete
Show Answer
Sol. Most of the air conditioner uses compressed gas, which can cool the room or other places.

Q10. The separation of cream from milk by churning is due to- Separation of cream from milk by churning is due 
to _______:
(a) Gravitational force / gravitational force 
(b) Cohesive force / united force 
(c) Centrifugal force / postural force 
( d) None of the above / None of the above
Show Answer
Sol. The separation of cream from milk by churning is due to centrifugal force.

Q11. The clouds float in the atmosphere because of their low: 
clouds fly due to their low __________ in the atmosphere  
(a) Temperature / temperature 
(b) Velocity / velocity 
(c) Pressure / pressure 
(d) Density / density
Show Answer
Sol. Clouds form when the invisible water vapour in the air condenses into visible water droplets. They are so small that the effect of gravity on them is negligible. Thus the clouds float in the atmosphere because of their low density.

Q12. Which of the following elements was first produced artificially? 
Which of the following elements was first artificially created? 
(a) Neptunium / Neptunium 
(b) Plutonium / Plutonium 
(c) Francium / Francium 
(d) Technetium / Technetium
Show Answer
Sol. Technetium is a chemical element with atomic number 43. It was the first artificially produced element. Technetium was isolated by Carlo Perrier and Emilio Segre in 1937.

Q13. While floating in a sea what is an iceberg is the surface of the sea? 
Which part of a iceberg is floating above sea level while swimming in a sea? 
(a) 1/9 
(b) 1/10 
(c) 1/6 
(d) 1/4
Show Answer
Sol. When pure water changes into the ice at 4°C, the density of ice so formed is 1/9th of the density of water. Therefore, in pure water, 90% part of the ice must be below the surface of the water and remaining 10% part must be above the surface, Sea water has high density (salty) water but the ice formed by it is pure and not salty.

Q14. Why is it easy to swim in the sea than in a river? 
Why is it easier to swim in the sea than a river? 
(a) The sea water is salty / sea water is salted 
(b) The sea water is deep / sea water is deep 
(c) The sea water is heavy / sea water is heavy 
(d) The sea water is lighter / Sea water is light
Show Answer
Sol. It is easier to swim in sea water than in river because, the sea water contains salt which increases the density of water and also increases its upthrust so, the chances of sinking get reduced and one can easily swim in such water.

Q15. When a ship enters a sea from a river, what happens? 
What happens when a ship enters the sea from the river? 
(a) It rises a little / She comes to a slightly higher level. 
(b) It remains at the same level / its level remains the same. 
(c) It sinks a little / its level gets reduced slightly. 
(d) It is immersed in the sea completely.
Show Answer
Sol. When a ship enters a sea from a river, the ship is elevated due to the higher density of salty sea water than the river.