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.

731.

Which of the following surfaces will absorb radiant heat energy?

A.

white

B.

red

C.

black

D.

blue

Correct answer is C

A black solution is a better radiator of heat and allow a better absorber of heat.

732.

Which of the following is a semiconductor

A.

copper

B.

silicon

C.

plastic

D.

Iron

Correct answer is B

Semi-conductor have an elecctric conductivity intermediate in value between that of a pure metal and a good insulator. Silicon is an example

733.

Which of the following is correct about an electric cell?

A.

Primary cell produces a large current for a long time

B.

Secondary cell has a very high internal resistance

C.

Primary cell has a very low internal resistance

D.

Secondary cell has a very low internal resistance

Correct answer is D

About electric cell
Primary cells are used up gradually often the cells are use and it can't be recharged
Secondary cells or accumulated can be recharged and used for a long period of time and their main advantage is that they have low internal resistance

734.

I. Refraction II. Interference III. Diffraction Which of the above properties are common to all waves?

A.

II and III only

B.

I, II and III

C.

I and II only

D.

I and III only

Correct answer is B

Refraction, Interference and diffraction are all properties of waves

735.

A constant force of 5N acts for 5 seconds on a mass of 5kg initially at rest. Calculate the final momentum

A.

125kgms−1

B.

25kgms−1

C.

15kgms−1

D.

0kgms−1

Correct answer is B

Impulse = momentum

Impulse = Force (f) × time (t)

Momentum = mass (m) × velocity (v)

∴ Ft = Final momentum - initial momentum

FT = mv - mu

Since it is initially at rest u = 0

∴ 5 × 5 = mv − m(0)

25 = mv

∴ Final momentum = 25kgms\(^{-1}\)