Post Utme Physics Past Questions and Answers

Question 256:

A cell of internal resistance 2 ohms supplies current to a -6ohm resistor. The efficiency of the cell is ____________

A. \(12.0 \%\)
B. \(25.0 \%\)
C. \(33.3 \%\)
D. \(75.0 \%\)

Question 257:

The length of a side of metallic cube at \(20^{\circ} \mathrm{C}\) is \(5.0 \mathrm{~cm}\).

Given that the linear expansivity of the metal is \(4.0 \times 10^{-5} \mathrm{k}^{-1}\). Find the volume of the cube at \(120^{\circ} \mathrm{C}\).

A. \(126.50 \mathrm{~cm}^{3}\)
B. \(126.25 \mathrm{~cm}^{3}\)
C. \(126.00 \mathrm{~cm}^{3}\)
D. \(125.00 \mathrm{~cm}^{3}\)

Question 258:

As a result of air at the top of a barometer, the height of the mercury column is \(73.5 \mathrm{~cm}\) when it should be \(75.0 \mathrm{~cm}\); the volume of the space above the mercury is \(8.0 \mathrm{~cm}^{3}\).

Calculate the correct barometric height when the barometer reads \(74.0 \mathrm{~cm}\) and the volume of the space above the mercury is \(6.0 \mathrm{~cm}^{3}\).

A. \(72.0 \mathrm{~cm}\)
B. \(74.5 \mathrm{~cm}\)
C. \(75.1 \mathrm{~cm}\)
D. \(76.0 \mathrm{~cm}\)

Question 259:

A wave has a frequency of \(2 \mathrm{~Hz}\) and a wavelength of \(30 \mathrm{~cm}\). The velocity of the wave is ____________

A. \(60.0 \mathrm{~ms}^{-1}\)
B. \(6.0 \mathrm{~ms}^{-1}\)
C. \(1.5 \mathrm{~ms}^{-1}\)
D. \(0.6 \mathrm{~ms}^{-1}\)

Question 260:

If the distance between two stationary charged particles is doubled, the magnitude of the electrostatic force between them will be ____________

A. Doubled
B. Halved
C. A quarter of its former value
D. Unchanged
E. Four times the original value