Which of the following is connected to the coil of the galvanometer, to protect it from possible damages due to large current?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Low resistance wire in parallel
A galvanometer coil can carry only a very small current. A low resistance in parallel, called a shunt, takes most of a large current past the coil, so only a small safe part flows through the coil. In parallel, the currents divide in the inverse ratio of the resistances:
\( \displaystyle \frac{I_g}{I_s} = \frac{S}{G} \)
With \( S \) much smaller than \( G \), the coil current \( I_g \) is a small fraction of the total. This is also how a galvanometer is converted into an ammeter.
Why the other options are incorrect
Option (1) High resistance wire in parallel — Incorrect. A high resistance in parallel takes very little current, so almost all of a large current still passes through the coil.
Option (3) High resistance wire in series — Incorrect. A high resistance in series is how a galvanometer is converted into a voltmeter; it does not divert a large current in the circuit away from the coil, it limits the current of the whole branch.
Option (4) Low resistance wire in series — Incorrect. A low resistance in series carries the same current as the coil and hardly reduces it, so the coil is not protected.
Note: The same question was also asked in CUET (UG) 2023 on 02-07-2023 (Slot 3).
NCERT (2026-27):
The Moving Coil Galvanometer – “… (i) Galvanometer is a very sensitive device, it gives a full-scale deflection for a current of the order of µA. … To overcome these difficulties, one attaches a small resistance rs, called shunt resistance, in parallel with the galvanometer coil; so that most of the current passes through the shunt.”