Post Utme Physics Past Questions and Answers

Question 791:

Which of the following could be effectively used to reduce friction?

A. Kerosene
B. Grease
C. Water
D. Petrol
PHYSICS

Question 792:

A copper wire was subjected to a tensile stress of \(7.7 \times 106 \mathrm{Nm}^{-2}\) calculate the tenslle strain of the wire.
[young modulus \(=1.1 \times 1011 \mathrm{Nm}^{-2}\) ]

A. \(2.0 \times 10^{-5}\)
B. \(7.0 \times 10^{-3}\).
C. \(7.0 \times 10^{-4}\)
D. \(2.2 \times 10^{4}\)

Question 793:

An object welghs \(22 \mathrm{~kg}\) in water and 30 \(\mathrm{kg}\) in air. What is the up thrust exerted by the liquid on the object?
\(\left[\mathrm{g}=10 \mathrm{~ms}^{-2} \right]\)

A. \(50 N\)
B. \(520 \mathrm{~N}\)
C. \(220 \mathrm{~N}\)
D. \(80 \mathrm{~N}\)

Question 794:

A block of aluminium is heated electrically by a \(30 \mathrm{~W}\) heater. If the temperature rises by \(10^{\circ} \mathrm{C}\) in 5 minutes, the eat capacity of the aluminium is ____________

A. \(900 \mathrm{jk}^{-1}\)
B. \(90 \mathrm{jk}^{-1}\)
C. \(100 \mathrm{jk}^{-1}\)
D. \(200 \mathrm{jk}^{-1}\)

Question 795:

A perfect emitter or absorber of radiant energy is a ____________

A. Conductor
B. Black body
C. White body
D. Red body