Electrical Energy and Power - Jamb Physics Past Questions and Answers

Question 26:

• JAMB 2001

The cost of running five 60 W lamps and four 100 W lamps for 20 hours if electrical energy cost #10.00 per kwh is

A. 280.00
B. 160.00
C. 120.00
D. 140.00

Question 27:

• JAMB 2001

The primary coil of a transformer has N turns and is connected to a 120 V a.c. power line. If the secondary coils has 1 000 turns and a terminal voltage of 1 200 volts, what is the value of N?

A. 120
B. 100
C. 1 000
D. 1 200

Question 28:

• JAMB 2001

A bread toaster uses a current of 4A when plugged in a 24oV line. it takes 1 minute to toast slices of bread. what is the energy consumed by the toaster

A. 5.76 x 10⁴J
B. 1.60 x 10⁴J
C. 3.60 x 10³J
D. 1.60 x 10²J

Question 29:

• JAMB 2002

When connected to a mains of 250V, the fuse rating in the plug of an electric device of 1 KW is

A. 2 A
B. 3 A
C. 4 A
D. 5 A

Question 30:

• JAMB 2002

From the generating station to each substation power is transmitted at a very high voltage so as to reduce

A. Hysteresis loss
B. Eddy current loss
C. Magnetic flux leakage
D. Heating in the cells