JEE Main · 2021 · 31 Aug 2021 · Shift 1 · Current Electricity

Consider a galvanometer shunted with

5Ω

resistance and

2%

of current passes through it. What is the resistance of the given galvanometer?

Answer: (D)

Solution

The shunt and the galvanometer share the same voltage, so

i_{g} R_{g} = i_{s} R_{s}

. With

2%

of the current through the galvanometer,

i_{g} = 0.02 I

and

i_{s} = 0.98 I

. Thus

0.02 I \cdot R_{g} = 0.98 I \cdot 5

, giving

R_{g} = \frac{0.98 \times 5}{0.02} = 245 Ω.

JEE Main · 2021 · 31 Aug 2021 · Shift 1 · Single correct option