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.

1,706.

As a bicycle Tyre was being pumped up, it was noticed that contrary to Boyle's law the volume increased as the pressure increased. The best explanation of this is that Boyle's law is only true for

A.

ideal gases

B.

a fixed mass of gas

C.

a mixture of gases

D.

a gas at variable temperature

Correct answer is A

No explanation has been provided for this answer.

1,707.

A rod of initial length 2m at a temperature of 25oC is heated to 80oC. Calculate the increase in length of the rod if its linear expansivity is 4.0 x 10-3K-1

A.

0.26m

B.

0.44m

C.

0.53m

D.

0.84m

Correct answer is B

\(l_2 - l_1 = \alpha l_1 (\theta_2 - \theta_1) = 4.0 \times 10^{-3} \times 2(80 - 25)\)

= 0.44m

1,708.

A faulty thermometer registers 102.5oC t 100oC. If the thermometer has no zero hour, what will it register at 55oC?

A.

54.6oC

B.

55.0oC

C.

56.0oC

D.

56.4oC

Correct answer is D

x = \(\frac{102.5 \times 55}{100}\)

= 56.375oC

1,709.

A machine of efficiency 80% is used to lift a box. If the effort applied by the machine is twice the weight of the box. Calculate the velocity ratio of the machine

A.

0.50

B.

0.63

C.

0.80

D.

1.60

Correct answer is B

Y = \(\frac{M.A}{V.R} \times \frac{100}{1}\)

= \(\frac{\frac{1}{2}}{V.R} \times \frac{100}{1}\)

V.R = 0.625

1,710.

A stone of mass 0.5kg is dropped from a height of 12m. Calculate its maximum kinetic energy. [g = 10ms-1]

A.

3.0J

B.

6.0J

C.

30.0J

D.

60.0J

Correct answer is D

K.E = P.E = mgh

= 0.5 x 10 x 12 = 60J