WAEC Physics Past Questions & Answers - Page 199

991.

A resistance thermometer has a resistance of 20\(\Omega\) at 0oC and 85\(\Omega\) at 100oC. If its resistance is 52\(\Omega\)in a medium, calculate the corresponding temperature

A.

49.2oC

B.

60.6oC

C.

80.0oC

D.

84.7oC

Correct answer is A

85\(\Omega\) ........100oC

52\(\Omega\) ........\(\theta\)oC

20\(\Omega\) ........0oC

\(\frac{52 - 20}{85 - 20} = \frac{\theta - 0}{100 - 0}\)

\(\theta = \frac{32 \times 100}{65} = 49.2^oC\)

992.
994.

A simple machine with an efficiency of 75% lifts a load of 5000N when a force of 500N is applied to it. Calculate the velocity ratio of the machine

A.

10.0

B.

13.3

C.

17.5

D.

25.0

Correct answer is B

M.A = \(\frac{load}{effort} \frac{5000N}{500N} = 10\)

V.R = \(\frac{M.A \times 100}{V} = \frac{10 \times 100}{75} = 13.3\)

995.

Electrical resistance is a property of an electrical energy to be converted into

A.

mechanical energy

B.

heat energy

C.

magnetic energy

D.

chemical energy

Correct answer is B

No explanation has been provided for this answer.