Post Utme Physics Past Questions and Answers

Question 511:

How long does it take a 800 W heater to raise the temperature of \(2 kg\) of water from \(20 \circ C\) to \(60 \circ C\) ?
(specificheat capacity of water \(=4200 J / kg . K\) )

A. \(280 s\)
B. \(420 s\)
C. \(210 s\)
D. \(120 s\)

Question 512:

A room is heated by means of charcoal fire. A man in the room standing away from the fire is warmed by ____________

A. Convection
B. Radiation
C. Conduction
D. Reflection

Question 513:

What is the relative permittivity of a capacitor if its capacitance with a medium as dielectric is 16 farads and its capacitance with vacuum as dielectric is 2 farads?

A. 1/3
B. 1/2
C. 2
D. 8
E. 32

Question 514:

If the magnification of a virtual image formed of an object 10cm from a convex lens is 3, the focal length of the lens is ____________

A. 10cm
B. 7.5cm
C. 16cm
D. 19cm
E. 20cm

Question 515:

If a water pump at Kainji Dam is capable of lifting 1000kg of water through a vertical height of 10m in 10s, the power of the pump is ____________
(g=10m/s²)

A. 1.0 kW
B. 10.0 kW
C. 12.5 kW
D. 15.0 kW
E. 20.0 kW