Physics Test 25

Total Questions: 25

1 - What are primary colours?

A ) Colour of the rainbow
B ) Colour in the spectrum of white light
C ) Colours which cannot be produced ✅
D ) Colour found in nature

2 - Air bubble in water shines because of the phenomenon of

A ) Dispersion
B ) Refraction
C ) Diffraction
D ) Total internal reflection ✅

3 - Sun and the other stars are virtually huge nuclear explosion chambers producing a large amount of heat and light. Yet,we do not hear any of the explosions because

A ) Heat and light are electromagnetic radiations and travel much faster than sound
B ) Sound waves get attenuated completely before they reach the earth
C ) The process involved in the interior of the sun and the stars relate to atomic and subatomic particles and not molecules and their vibrations
D ) The outer space is an absolute vacuum ✅

4 - The advantage of AC over DC is that

A ) It contains more electrical energy
B ) It is free from voltage fluctuations
C ) Its generation costs much less
D ) It can be transmitted over long distances with minimum power loss ✅

7 - The spherical shape of a small drop of rain is due to

A ) Viscosity
B ) Surface tension ✅
C ) Atmospheric pressure
D ) Gravity

8 - The blue colour of the sky can be attributed to

A ) Differential scattering of sunlight by the atmosphere ✅
B ) Total internal reflection of the sunlight by the atmosphere
C ) Absorption of sunlight
D ) Refraction of sunlight by the atmosphere

9 - Which one of the following sets of properties are relevant for an electrical fuse wire needed for normal application?

A ) Thick wire,high melting point alloy,short length ✅
B ) Thick wire,low melting point alloy,large length
C ) Shirt length,low melting point alloy,thin wire
D ) Large length,low melting point alloy, thin wire

12 - Which of the following can be used to focus sunlight?

A ) Plane mirror
B ) Concave mirror ✅
C ) Concave lens
D ) Convex mirror

13 - Which of the following is a good conductor of electricity?

A ) PVC
B ) Glass
C ) Rubber
D ) Graphite ✅

14 - The tendency of a liquid drop to contract and occupy minimum area is due to

A ) Surface tension ✅
B ) Viscosity
C ) Density
D ) Vapour pressure

15 - Choke coil is a coil of

A ) High resistance and high inductance
B ) Low resistance and high inductance ✅
C ) High resistance and low inductance
D ) Low resistance and low inductance

16 - Conductors,insulators and semi-conductors different from each other due to property of

A ) Ability of the current they carry
B ) Formation of crystal lattice
C ) Binding energy of their electrons
D ) Mutual width of their energy gaps ✅

17 - On which principle does the tape-recorder function?

A ) Electromagnetic Induction ✅
B ) Electrovalency
C ) Gay Lussac's law of combining volumes
D ) Boyle's law

18 - When a constant force is applied to a body it moves with uniform

A ) Momentum
B ) Velocity ✅
C ) Speed
D ) Acceleration

19 - The silvered surface of thermoflask prevents transfer of heat by

A ) Conduction
B ) Convection
C ) Reflection
D ) Radiation ✅

20 - When wind blows at high velocity,root tops are blown off because pressure

A ) Outside is more than inside the roof
B ) Inside is more than outside the roof ✅
C ) Increase due to wind velocity
D ) Is exerted by air from outside

21 - Tube light works on the principle of

A ) Chemical effect of current
B ) Heating effect of current
C ) Magnetic effect of current
D ) Discharge of electricity through gases ✅

22 - In a refrigerator, cooling is produced by

A ) The rice which deposits on the freezer
B ) The evaporation of a volatile liquid ✅
C ) The sudden expansion of a compressed gas
D ) None of these

23 - Air is completely removed from an electric bulb to prevent

A ) Oxidation of tungsten filament ✅
B ) Bursting of the bulb
C ) Loss of light due to absorption
D ) None of these

24 - A person climbing a hill bends forward in order to

A ) Avoid slipping
B ) Increase speed
C ) Reduce fatigue
D ) Increase stability

25 - On earth a moving body ordinarily comes to rest by itself because of the

A ) Law of inertia
B ) Forces of friction ✅
C ) Conservatism of momentum
D ) Gravity