Post Utme Physics Past Questions and Answers

Question 271:

I. The frictional force is independent of the area of the surfaces in contact
II. The frictional force depends on the nature of the surfaces in contact.
III. The frictional force depends on the speed of the sliding.
IV. The frictional force is directly proportional to the normal reaction.
Which combination of the above is true of sliding friction?

A. I, II and IV
B. I, II and III
C. I, III and IV
D. II, III and IV

Question 272:

The electrochemical equivalent of a metal is \(0.126 \times 10^{-6} \mathrm{~kg} / \mathrm{C}\). The mass of the metal that a current of \(5 \mathrm{~A}\) will deposit from a suitable bath in 1 hour is ____________

A. \(0.0378 \times 10^{-3} \mathrm{~kg}\)
B. \(0.227 \times 10^{-3} \mathrm{~kg}\)
C. \(0.378 \times 10^{-3} \mathrm{~kg}\)
D. \(2.268 \times 10^{-3} \mathrm{~kg}\)

Question 273:

Which of the following is in a neutral equilibrium

A. A heavy weight suspended on a string
B. A cone resting on its slant edge
C. A heavy-based table lamp
D. The beam of a balance in use

Question 274:

Which of the following instruments has a pure tone?

A. Guitar
B. Vibrating string
C. Tuning fork
D. Siren

Question 275:

If a radioactive substance with a half-life of 3 minutes remains \(400 \mathrm{~g}\) after 6 minutes, what is the original mass of the substance?

A. \(800 \mathrm{~g}\)
B. \(2400 \mathrm{~g}\)
C. \(600 \mathrm{~g}\)
D. \(1600 \mathrm{~g}\)