WAEC Physics Past Questions & Answers - Page 170

846.

Which of the following values on the absolute scale of temperature is the ice point?

A.

0K

B.

32K

C.

100K

D.

273k

Correct answer is D

No explanation has been provided for this answer.

847.

When compared with water, mercury is preferred as a thermometric liquid because

A.

has a higher density

B.

has lower specific heat capacity

C.

exhibits anomalous thermal expansion

D.

contains molecules which have very strong adhesive forces

Correct answer is B

Specific Heat Capacity of mercury and water are 0.14 Jg\(^{-1}\)C\(^{-1}\) and 4.186Jg\(^{-1}\)C\(^{-1}\) respectively.

848.

A loaded spring performs simple harmonic motion with an amplitude of 5cm. If the maximum acceleration of the load is 20cm s-1, calculate the angular frequency of the motion

A.

2 rad s-1

B.

4 rad s-1

C.

5 rad s-1

D.

10 rad s-1

Correct answer is A

= \(\frac{v}{g} = \frac{0.2}{0.05}\)

where w = √ 4 → 2rad s-1

849.

A ball bearing is projected vertically upwards from the ground with a velocity of 15ms-1. Calculate the time taken by the ball to return to the ground [g = 10ms-1]

A.

1.5s

B.

3.0s

C.

5.0s

D.

7.5s

Correct answer is B

t = 2\(\frac{(v - u)}{g} = 2\frac{(0 - 15)}{-10}\)

\(\frac{2 \times 15}{10}\) = 3.0s

850.

The bob of a single pendulum has a mass of 0.02kg. Determine the weight of the bob [g = 10ms-2]

A.

0.02N

B.

0.20N

C.

20.00N

D.

200.00N

Correct answer is B

Wt = mg = 0.02 x 10 = 0.2N