Simple A. C. Circuits - Jamb Physics Past Questions and Answers

Question 21:

• JAMB 2006

A 120 V, 60 W lamp is to be operated on 220 V a.c. the supply mains. calculate the values of non-inductive resistance that would be required to ensure that the lamp is run on current value.

A. 100 Ω
B. 200 Ω
C. 300 Ω
D. 500 Ω

Question 22:

• JAMB 2007

The instantaneous value of the induced e.m.f as a function of time is ε = ε_o sin ωt where ε_o is the peak value of the e.m.f. The instantaneous value of the e.m.f., one quarter of the period is

A. 0.00
B. ^ε_o/₄
C. ^ε_o/₂
D. ε_o

Question 23:

• JAMB 2007

from the diagram above, the inductive reactance and the resistance R are respectively

A. 50Ω and 45Ω
B. 25Ω and 51Ω
C. 20Ω and 50Ω
D. 10Ω and 50Ω

Question 24:

• JAMB 2007

A 120V, 60W lamp is to be operated on 220V ac supply mains. calculate the value of non inductive resistance that would be required to ensure that the lamp is run on correct value

A. 100Ω
B. 200Ω
C. 300Ω
D. 500Ω

Question 25:

• JAMB 2008

An electric generator has e.m.f. of 240 V and an internal resistance of 1Ω if the current supplied by the generatoris 20A when the terminal voltage is 220 V, find the ratio of the power supplied to the power dissipated?

A. 11:1
B. 1:11
C. 12:11
D. 11:12