Commercial unit of electric energy and power - Jamb Physics Past Questions and Answers

Question 1:

• JAMB 2019

If the time of flight is 96seconds, calculate the horizontal range through the point of projection.

A. 84400m
B. 69000m
C. 61440m
D. 24000m

Question 2:

• JAMB 1988

A household refrigerator is rated 200 watts. If electricity costs 5k per kWh, what is the cost of operating it in 20 days?

A. N4.80
B. N48.00
C. N480.00
D. N4800.00

Question 3:

• JAMB 1990

Which of the following is most suitable for protecting the circuit of 2000W electric iron connected to a 250V mains?

A. 13A
B. 8A
C. 5A
D. 3A

Question 4:

• JAMB 1991

An equipment whose power is 1500W and resistance is 375 ohms would draw a current of

A. 0.10A
B. 2.00A
C. 4.00A
D. 77.5A

Question 5:

• JAMB 1998

Electricity is supplied to a school along a cable of total resistance 0.5\(\Omega\) with the maximum current drawn from the mains as 100A. The maximum energy dissipated as heat for 1 hr is

A. 3.6 x 10³J
B. 5.0 x 10³J
C. 3.0 x 10⁵J
D. 1.8 x 10⁷J