Q. A candidate connects a moving coil voltmeter V, a moving coil ammeter A, and a resistor R as shown in figure. If the voltmeter reads 20 V and the ammeter reads 4A, R is

(a) equal to 5 Ω

(b) greater than 5 Ω

(c) less than 5 Ω

(d) greater or less than 5 Ω depending upon its material

Ans: (b)

Sol: Since , practically current through resistance R should be less than 4 A

I < 4

$\large \frac{20}{R} < 4$

Hence , R > 5 Ω