Post Utme Physics Past Questions and Answers

Question 276:

An object placed \(36 \mathrm{~cm}\) from a converging lens of focal length \(20 \mathrm{~cm}\) forms a real image which is \(40 \mathrm{~cm}\) high. What is the height of the object?

A. \(30 \mathrm{~cm}\)
B. \(22 \mathrm{~cm}\)
C. \(32 \mathrm{~cm}\)
D. \(45 \mathrm{~cm}\)

Question 277:

Which of the following statements about defects of vision is/are CORRECT?
I. For a long-sighted person, close objects appear blurred.
II For a short-sighted person, distant objects appear blurred.
III. Short sight is corrected by using a pair of converging lenses.

A. I and II only
B. II only
C. I only
D. II and III only

Question 278:

The total length of a spring when a mass of \(20 \mathrm{~g}\) is hung from its end is \(14 \mathrm{~cm}\), while its total length is \(16 \mathrm{~cm}\) when a mass of \(30 \mathrm{~g}\) is hung from the same end. Calculate the unstretched length of the spring assuming Hooke's law is obeyed.

A. \(9.33 \mathrm{~cm}\)
B. \(12.00 \mathrm{~cm}\)
C \(10.00 \mathrm{~cm}\)
C. \(10.66 \mathrm{~cm}\)

Question 279:

A milliammeter with full scale deflection of \(10 \mathrm{~mA}\) has an internal resistance of 5 ohms. It would be converted to an ammeter with a full-scale deflection of \(1 \mathrm{~A}\) by connecting a resistance of ____________

A. \(99 / 5\) ohm in series with it
B. \(99 / 5\) ohm in parallel with it
C. \(5 / 99\) ohm in parallel with it
D. \(5 / 99\) ohm in series with it

Question 280:

What precaution should a manufacturer take to ensure that energy loss in a transformer is minimized?

A. The winding of the transformer should be made of high resistance wires.
B. The core should be made of thin sheets of metal.
C. No magnetic material should be used to make the core.
D. The flux linking the primary with the secondary coils should be minimum