Question 571: Current Electricity

Question

In conversion of moving coil galvanometer into an ammeter of required range, the resistance of ammeter, so formed is
[$S=$ shunt and $G=$ resistance of galvanometer]

Accepted Answer

To convert a moving coil galvanometer into an ammeter with a specific range, you need to connect a low resistance, known as a shunt resistance, in parallel with the galvanometer. This helps the galvanometer measure higher currents by bypassing most of the current through the shunt.
The resistance $ R $ of the resulting ammeter is calculated using the formula for parallel resistances:
$ \frac{1}{R} = \frac{1}{S} + \frac{1}{G} $
Solving for $ R $, we get:
$ R = \frac{S \cdot G}{S + G} $
Here, $ S $ represents the shunt resistance, and $ G $ is the resistance of the galvanometer.

Answer

$\frac{S+G}{S G}$

Answer

$\frac{S G}{S+G}$

Answer

$\frac{S-G}{S G}$

Answer

$\frac{S G}{S-G}$

Current Electricity

In conversion of moving coil galvanometer into an ammeter of required range, the resistance of ammeter, so formed is [S= shunt and G= resistance of galvanometer]

Choose the correct answer: