WAEC Physics Past Questions & Answers - Page 104

517.

Which of the following equations shows how how the linear expansivity (\(\alpha\)) and the cubic expansivity (\(\gamma\)) of a material are related?

A.

\(\gamma = \alpha\)

B.

\(\gamma = 1 - \alpha\)

C.

\(\gamma = 2 \alpha\)

D.

\(\gamma = 3 \alpha\)

Correct answer is D

No explanation has been provided for this answer.

518.

A hypsometer is used for determining

A.

steam point

B.

relative humidity

C.

ice point

D.

relative density

Correct answer is A

No explanation has been provided for this answer.

519.

The radius of a wheel is 30.0 cm and that of its axle is 6.0cm. Calculate the effort required to lift a load of 120.0N using this machine. Assuming 100% efficiency

A.

600.0N

B.

40.0N

C.

24.0N

D.

20.0N

Correct answer is C

V.R = \(\frac{R}{r} = \frac{30}{6} = 5\)

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

M.A = \(\frac{100 \times 5}{100} = 5\)

Effort = \(\frac{L}{M.A} = \frac{120}{5}\)

= 24N

520.

Which of the following statements correctly defines a simple machine? A device

A.

that can produce electric current

B.

which can only carry people from one place to another

C.

with which work can be done easily

D.

which changes the state of rest or of uniform motion of an object

Correct answer is C

No explanation has been provided for this answer.