Current Electricity - Jamb Physics Past Questions and Answers

Question 96:

• JAMB 2003

A wire of 5Ω resistance is drawn out so that its new length is two times the original length. If the resistivity of the wire remains the same and the cross-sectional area is halved, the new resistance is

A. 40Ω
B. 20Ω
C. 10Ω
D. 5Ω

Question 97:

• JAMB 2004

A steady current of 2A flows in a coil of emf 12V for 0.4s. A back emf of 3V was induced during this period. The stored energy in the loop that can be utilized is

A. 9.6J
B. 2.4J
C. 12.0J
D. 7.2J

Question 98:

• JAMB 2004

In the diagram above, the ratio of he electric power dissipated in the 6Ω and the 3Ω resistor respectively is

A. 2:1
B. 2:2
C. 1:3
D. 1:2

Question 99:

• JAMB 2004

A cell whose internal resistance is 0.5Ω delivers a current of 4A to an external resistor,The loss voltage of the cell is

A. 1.250V
B. 2.000V
C. 8.000V
D. 0.125V

Question 100:

• JAMB 2005

The resistance of a pieces of wire of lenght 20m are crossed-sectional area 8 x 10 ⁶m²is?
[Resistivity of the wire = 4 x 10^-7 Ω m]

A. 5.0 Ω
B. 0.5 Ω
C. 10.0 Ω
D. 1.0 Ω