Physics Test 27

Total Questions: 25

1 - When light enters from rare to denser medium,it bends towards the normal line,it is called:

A ) Reflection of light
B ) Diffraction of light
C ) Refraction of light ✅
D ) Absorption of light

2 - Electromagnetic waves travel with the

A ) Speed of light ✅
B ) Speed of sound
C ) Speed of earth rotation
D ) Speed of sun rotation

3 - Sound travels faster in:

A ) Dry air than in water
B ) Wood than in iron
C ) Iron than in air ✅
D ) Hydrogen than in water

5 - On passing through food stuff, x-ray can kill the

A ) Fungus
B ) Virus
C ) Bacterials ✅
D ) Insects

6 - Which of the following gives correct descending order of elastically in the substances?

A ) Rubber,silver,glass
B ) Silver,rubber,steel
C ) Steel,silver, rubber ✅
D ) All have equal elastically

8 - A Polaroid is

A ) A red light filter
B ) A device used for analysing polarized light ✅
C ) A device used in polarimeter
D ) An adjustable shutter

10 - The phenomenon of land and sea breeze is as a result of

A ) Conduction
B ) Convection ✅
C ) Radiation
D ) None of these

11 - The weight of a given object is maximum

A ) At the bottom of a 500 ft. deep mine
B ) At the top of a mountain 5,000 ft high
C ) At a distance of 100 km above the earth's surface
D ) At the surface of the earth ✅

12 - The flow of heat from a hot to a cold body is an example of

A ) Adiabatic process
B ) Irreversible process
C ) Reversible process
D ) Isothermal process ✅

13 - What makes the air coming out of a punctured tyre cool?

A ) Adiabatic expansion ✅
B ) Flow at high speed
C ) Isothermal expansion
D ) None of these

14 - It takes much longer to cook things in the hills than in the plains, because:

A ) Atmospheric pressure is high in the hills and water boils at a higher temperature
B ) Atmospheric pressure is lower and water boils at a lower temperature ✅
C ) Due to low atmospheric pressure in the hills the boiling point of water is raised and therefore water takes longer to boil
D ) The humid atmosphere in the hills absorbs a lot of heat, leaving very little for the cooking

15 - The working of optical fibers is based on the........of electromagnetic waves.

A ) Refraction
B ) Reflection
C ) Total internal reflection ✅
D ) Polarization

16 - The needle of a magnetic compass

A ) Is affected only by permanent magnetics
B ) Rotates in the magnetic field of an electric current
C ) Aligns itself parallel to a magnetic field ✅
D ) Aligns itself perpendicular to a magnetic field

17 - Which of the following is true for capacitors in series?

A ) The total capacitance is the sum of the individual capacitance
B ) The total charge is the sum of the charges on each capacitor
C ) The total voltage is the sum of the voltage across each capacitor ✅
D ) The available charge is shared between two or more capacitors

18 - Condenser is used

A ) To produce charge
B ) To change the direction of current
C ) To collect the charge ✅
D ) As a good conductor of electricity

19 - All the following statements are correct, except

A ) The presence of moisture in the air reduces the conductivity of charge ✅
B ) When a body is charged positively,some electrons escape from it
C ) A body is said to be negatively charged when it has got some electrons
D ) None of the above statements is correct

20 - Two parallel wires carrying currents in the opposite direction

A ) Attract each other ✅
B ) Repel each other
C ) Do not exert any force on each other
D ) None of these

21 - A car is running on a road at a uniform speed of 60 km/hr. The net resultant force on the car is:

A ) Driving force in the direction of car's motion
B ) Resistance force opposite to the direction of car's motion
C ) An inclined force
D ) Equal to zero ✅

22 - Which one of the following is not an advantage of AC over DC?

A ) The AC does skin effect ✅
B ) In AC a wid range of voltages is possible
C ) Lines loss in AC transmission lines are negligible
D ) In AC the magnitude of current can be reduced by a choke?

23 - Which of the following instruments may be used to measure A. C?

A ) Galvanometer
B ) Hot-wire ammeter ✅
C ) Moving coil galvanometer
D ) None of these

24 - Copper wires are generally used for electrical power transmission instead of iron wires because:

A ) Copper is a better conductor than iron ✅
B ) Copper is cheaper than iron
C ) Copper can take higher power than iron
D ) Copper is lighter than iron

25 - Permanent magnets are made from

A ) Diamagnetic substances
B ) Ferromagnetic substances ✅
C ) Paramagnetic substances
D ) Dielectric substances