Question

A resistance wire connected in the left gap of a metre bridge balances a $10\Omega$ resistance in the right gap at a point which divides the bridge wire in the ratio $3:2$. If the length of the resistance wire is $1.5m$, then the length of $1\Omega$ of the resistance wire is :

• A. $1.0\times {10}^{-1}m$
• B. $1.5\times {10}^{-1}m$
• C. $1.5\times {10}^{-2}m$
• D. $1.0\times {10}^{-2}m$

Answer 1

Answer: (A)

$1.0\times {10}^{-1}m$

Given,

$R:S=3:2$

$S=10\Omega$

Ratio, $\frac{R}{S}=\frac{3}{2}$

$R=\frac{3}{2}\times 10=15\Omega$

The length of $1\Omega$ wire is given by

$l=\frac{1.5}{15}$

$l=\frac{1}{10}\Rightarrow 0.1mor1.0\times {10}^{-1}m$

The correct option is A.