Physics questions and answers

Physics Questions and Answers

If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.

51.

Which of the following types of electromagnetic waves is used in night vision goggles?

A.

Microwaves

B.

Ultraviolet waves

C.

Infrared waves

D.

Radio waves

Correct answer is C

Infrared waves are used in night vision goggles because they can penetrate the darkness and allow people to see objects that are not visible to the naked eye

52.

In the diagram above, if the south poles of two magnets stroke a steel bar, the polarities at X and Y will respectively be

A.

south and north

B.

north and south

C.

north and north

D.

south and south

Correct answer is C

The polarities at X and Y would be north and north.

53.

Which of the following statements is correct about the angle of dip at various points on Earth?

A.

The angle of dip is zero at the equator and 90 degrees at the magnetic poles.

B.

The angle of dip is greater at higher altitudes than at lower altitudes

C.

The angle of dip is positive in the northern hemisphere and negative in the southern hemisphere

D.

The angle of dip is constant at all points on Earth

Correct answer is A

The angle of dip is the angle between the direction of the intensity of the total magnetic field of Earth and a horizontal line in the magnetic meridian. It is also known as the magnetic inclination. The angle of dip ranges from 0 degrees at the magnetic equator to 90 degrees at the magnetic poles.

54.

When a water droplet is placed on a freshly cut piece of wood, it spreads out to form a thin layer because the wood is

A.

not at equilibrium with the water

B.

cohesive to water

C.

at equilibrium with the water

D.

adhesive to water

Correct answer is D

Adhesive surfaces are surfaces that are wetted by water. This means that the water molecules are attracted to the wood surface, and they spread out to form a thin layer in order to maximize their contact with the surface. The adhesive forces between the water molecules and the wood surface are stronger than the cohesive forces between the water molecules, resulting in a thin layer.

55.

A positively charged particle is placed near a negatively charged particle. What is the direction of the electric force between the two particles?

A.

The electric force is directed from the negative particle to the positive particle

B.

The electric force is zero.

C.

The direction of the electric force cannot be determined.

D.

The electric force is directed from the positive particle to the negative particle.

Correct answer is D

The electric force between two charged particles is always directed from the positive particle to the negative particle. This is because opposite charges attract each other, while like charges repel each other.

56.

Which of the following is an example of a couple?

A.

All of the above.

B.

The forces that are applied to the handle of a screwdriver when you twist it.

C.

The forces that are applied to a cross wench to loosen or tighten the lug nuts on a wheel of a car.

D.

The forces that are applied to the steering wheel of a car when you turn it.

Correct answer is A

A couple is a pair of forces that are equal in magnitude but opposite in direction, and that are applied to a body at different points. The forces of a couple do not produce any translation, but they do produce a rotation.

57.

Which of the following is NOT an example of elementary modern physics?

A.

Classical mechanics

B.

Quantum mechanics

C.

Special relativity

D.

Nuclear physics

Correct answer is A

Classical mechanics is a branch of physics that deals with the motion of macroscopic objects. It is based on the principles of Newton's laws of motion and is not considered to be part of elementary modern physics.

The other three options, quantum mechanics, special relativity, and nuclear physics, are all considered to be part of elementary modern physics because they deal with the behavior of matter and energy at the atomic and subatomic levels.

58.

A generator manufacturing company accidentally made an AC generator instead of a DC generator. To fix this error,

A.

the magnetic field needs to be made stronger

B.

the split rings should be replaced with slip rings

C.

the number of turns of the armature coil needs to be decreased

D.

the slip rings should be replaced with split rings

Correct answer is D

An AC generator uses slip rings to transfer the induced current smoothly to the circuit. A DC generator uses split rings to transfer the induced current to the circuit and also convert the induced AC into pulsating DC. So, to convert an AC generator into a DC generator, the slip rings needs to be replaced with split rings.

59.

Which of the following materials is a good insulator?

A.

Silver

B.

Water

C.

Rubber

D.

Copper

Correct answer is C

Rubber is a good insulator because it does not allow electrons to flow through it easily. Copper, silver, and water are all good conductors of electricity.

60.

The electrolyte used in the Nickel-Iron (NiFe) accumulator is

A.

dilute tetraoxosulphate(VI) acid

B.

barium chloride solution

C.

potassium hydroxide solution

D.

sodium hydroxide solution

Correct answer is C

The electrolyte used in the Nickel-Iron (NiFe) accumulator is potassium hydroxide solution. It is a non-flammable, non-toxic, and relatively stable electrolyte. It is also a good conductor of electricity, which is important for the operation of the battery.