Question

A wire potentiometer of length 11 m and resistance $1\Omega /m$ balances a standard cell voltage of 1.018 V at a length of 10 m 18 cm. If the voltage of the battery supplying the current through the potentiometer is 2.0 V, then the value of the series resistance connected to the potentiometer is

• A. $9\Omega$
• B. $90\Omega$
• C. $900\Omega$
• D. $990\Omega$

Answer 1

The correct option is A $9\Omega$


Working current,

$I_w=\frac{1.018}{10.18}=0.1A$

Now, applying KVL,

$2=(R_S+11)0.1$

$\Rightarrow R_s=9\Omega$