A meter bridge is set up as shown in figure, to determine an unknown resistance $X$ using a standard $10…

A meter bridge is set up as shown in figure, to determine an unknown resistance $X$ using a standard $10 \Omega$ resistor. The galvanometer shows null point when tapping key is at $52 \mathrm{~cm}$ mark. The end-corrections are $1 \mathrm{~cm}$ and $2 \mathrm{~cm}$ respectively for the ends $A$ and $B$. The determined value of $X$ is
  1. $10.2 \Omega$
  2. $10.6 \Omega$
  3. $10.8 \Omega$
  4. $11.1 \Omega$

Solution

Using the concept of balanced Wheatstone bridge, we have $ \begin{array}{rlrl} & \frac{P}{Q} & =\frac{R}{S} \\ \therefore & & \frac{X}{(52+1)} & =\frac{10}{(48+2)} \\ \therefore & & X & =\frac{10 \times 53}{50}=10.6 \Omega \end{array} $ $\therefore$ Correct option is (b). Analysis of Question Question is moderately tough, because normally end corrections are not taught in the coaching/schools in this type of problem

Asked in: JEE Advanced 2011 (Paper 1)

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