Waec Physics 2012 Past Questions and Answers

Question 36:

• WAEC 2012

Six dry cells each of e.m.f. 2.0 and internal resistance of 1.0\(\Omega\) are connected in parallel across a load of 3.0\(\Omega\). Calculate the effective current in the circuit.

A. 0.63A
B. 0.50A
C. 0.31A
D. 0.22A

Question 37:

• WAEC 2012

Two similar cells are used to light two similar lamps as illustrated in the diagrams above. In which of the circuit diagrams are the lamps brightest?

A. P
B. Q
C. R
D. S

Question 38:

• WAEC 2012

A 120\(\Omega\) resistor dissipates 8 kJ of heat in 20s. Calculate the current through the resistor

A. 5.8A
B. 6.9A
C. 30.0A
D. 33.3A

Question 39:

• WAEC 2012

The magnetic relay is a device used for

A. Timing in sports
B. Storing magnetic field
C. Readin the magnitude of magnetic flux
D. Controlling another circuit carrying larger current

Question 40:

• WAEC 2012

the core of a transformer is usually laminated in order to

A. Reduce magnetic leakage
B. Reduce eddy current
C. Prevent vibration of the transformer
D. Make magnetic reversal in the core much easier