Current Electricity - Jamb Physics Past Questions and Answers

Question 36:

• JAMB 1984

A galvanometer of resistance 5.0W has full-scale deflection for a current of 100mA. How would its range be extended to 1.0A? By placing a resistance of

A. \(\frac{5}{9}\)\(\Omega\) in parallel
B. \(\frac{9}{5}\)\(\Omega\) in series
C. 45\(\Omega\) in parallel
D. 45\(\Omega\) in series
E. \(\frac{9}{5}\)\(\Omega\) in parallel

Question 37:

• JAMB 1984

What is the resistance of the circuit shown above

A. 4Ω
B. 11Ω
C. 19/5Ω
D. 17/4Ω
E. 8Ω

Question 38:

• JAMB 1985

A cell gives a current of 0.15A through a resistance of 8\(\Omega\) and 0.3A. When the resistance is changed to 3\(\Omega\) the internal resistance of the cell is

A. 0.05\(\Omega\)
B. 1.00\(\Omega\)
C. 1.50\(\Omega\)
D. 2.00\(\Omega\)
E. 2.50\(\Omega\)

Question 39:

• JAMB 1985

Which of the following will convert a milliammeter to a voltmeter?

A. Low series resistance
B. Low parallel resistance
C. High series resistance
D. High parallel resistance
E. Parallel resistance equal to milliammeter resistance

Question 40:

• JAMB 1985

A wire P has half the diameter and half the length of a wire Q of similar material. The ratio of the resistance of P to that of Q is

A. 8 : 1
B. 4 : 1
C. 2 : 1
D. 1 : 1
E. 1 : 4