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.