Question

An ammeter of resistance R gives a full-scale deflection when a current of 2 A passes through it. If it is measured with a maximum current of 10 A, the required shunt is ______.

Options

• R

• `"R"/2`

• `"R"/4`

• 2R

Answer 1

An ammeter of resistance R gives a full-scale deflection when a current of 2 A passes through it. If it is measured with a maximum current of 10 A, the required shunt is `underlinebb("R"/4)`.

Explanation:

Given, l = 2A, l_max = 10A

Since, shunt resistance, S = `(lR)/(l_"max" - l)`

= `(2R)/(10 - 2) = 2/8R = 1/4R`