# A moving coil milliammeter having a resistance of 10 ohms gives full-scale deflection when a current of 5 mA is passed through it. If the instrument is to be used to measure current upto 1 A.

A moving coil milliammeter having a resistance of 10 ohms gives full-scale deflection when a current of 5 mA is passed through it. If the instrument is to be used to measure current upto 1 A.

### Right Answer is:

A resistance of 0.502 Ω must be connected parallel with the resistance of the ammeter

#### SOLUTION

As we know that in ammeter the resistance is connected is connected in parallel.

The resistance of milliammeter Rm = 10 ohms

Full scale deflection current Im = 5mA = 0.005A

To measure current upto 1 A. The Resistance of the shunt Rs

R_{s} = I_{m}R_{m} ⁄ (I − I_{m}) = (0.005 × 10) ⁄ (1 − 0.005)

**R _{s} = 0.5025 Ω**