Physics 2012 Jamb Past Questions and Answers

Question 111 :

• 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

Question 112 :

• JAMB 2012

A capacitor of 20 x 10^-12F and an inductor are joined in series. The value of the inductance that will give the circuit a resonance frequency of 200kHz is

A. I/16 H
B. I/8 H
C. I/64 H
D. I/32 H

Question 113 :

• JAMB 2012

The magnetic force on a charged particle moving with velocity v is

A. Proportional to both the magnitude of the charge and the velocity v
B. Independent of the magnitude of the charge
C. Proportional to the velocity v only
D. Proportional to the magnitude of the charge only

Question 114 :

• JAMB 2012

A copper cube weighs 0.25 N in air, 0.17N when completely immersed in paraffin oil and 0.15 N when completely immersed in water.The ratio of upthrust in oil to upthrust in water is

A. 3 : 5
B. 4 : 5
C. 7 : 10
D. 13 : 10

Question 115 :

• JAMB 2012

A wheel and axle is used to raise a load of 500 N by the application of an effort of 250 N. If the radii of the wheel and the axle are 0.4 cm and 0.1 cm respectively, the efficiency of the machine is

A. 20 %
B. 40 %
C. 50 %
D. 60 %