Electrical Energy and Power - Jamb Physics Past Questions and Answers

Question 11:

• JAMB 1990

Electrical power is transmitted at a high voltage rather than low voltage because the amount of energy loss is reduced due to

A. Heat dissipation
B. Production of eddy currents
C. Excessive current discharge
D. Excessive voltage distance

Question 12:

• JAMB 1990

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 wire
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

Question 13:

• 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 14:

• JAMB 1992

Which of the following apparatus will require the smallest fuse rating for its protection?

A. 60W, 240V
B. 60W, 40V
C. 40W, 12V
D. 40W, 5V

Question 15:

• JAMB 1993

The primary aim in high tension transmission is to

A. Minimize electrical energy losses due to heat production
B. Increase the rate of energy transfer by using high voltage
C. Increase the current in the wire
D. Generate electricity at high current and low voltage