Electrical Energy and Power - Jamb Physics Past Questions and Answers

Question 6:

• JAMB 1987

When a transformer has more secondary windings than primary windings, it

A. Has a smaller secondary current
B. Has a greater power output
C. Is a step-down transformer
D. Increases the total energy output

Question 7:

• 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 8:

• JAMB 1989

The function of a 5-A fuse included in a circuit supplying a household refrigerator with power is to keep the

A. Temperature of the refrigerator low and constant
B. Keep current supplied to the refrigerator below 5A
C. Voltage supply constant
D. Current supplies to the refrigeration

Question 9:

• JAMB 1990

Which of the following is an essential physical property of the wires used for making fuses?

A. Low density
B. High thermal conductivity
C. Low electrical resistivity
D. Low melting point

Question 10:

• 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