Inductance - Jamb Physics Past Questions and Answers

Question 6:

• JAMB 1998

The iron core of an induction coil is made from bundles of wire so as to

A. Minimize eddy-currents
B. Generate eddy-current
C. Prevent sparking at the contact breaker
D. Get the greatest posible secondary voltage

Question 7:

• JAMB 1999

At what frequency would a 10H inductor have a reactance of 2000Ω?

A. π/200Hz
B. π/100Hz
C. 100/Ï€Hz
D. 100Ï€Hz

Question 8:

• JAMB 2000

A 2H inductor has negligible resistance and is connected to a 50/Ï€ Hz A.C. Supply. The reactance of the inductor is

A. 200 Ω
B. 50 Ω
C. 100/π Ω
D. 25/π Ω

Question 9:

• JAMB 2012

The core of an efficient transformer should consist of laminated pieces of metal in order to

A. Increase the heat produced by increasing the eddy current
B. Increase the heat produced by reducing the eddy current
C. Reduce the heat produced by increasing the eddy current
D. Reduce the heat produced by reducing the eddy current

Question 10:

• JAMB 2012

Energy losses through eddy currents are reduced by using

A. Low resistance wires
B. Insulated soft iron wires
C. Few turns of wires
D. High resistance wires