In the given figure, the potentiometer wire, AB has a resistance of 5 Ω and length 10 m. The balancing length AJ for 0.4 V is nearly:
Answer & explanation
Correct answer: option 2
Current flowing in the circuit is $ I = \frac{\xi}{R_{eq}} = \frac{5}{5+4.5} = \frac{10}{19}A$
Let length of part AJ is l.
$\Rightarrow 0.5l\times \frac{10}{19} = 0.4$
$ l = \frac{0.4\times 2\times 19}{10} = 1.52m$
The correct answer is Option (2) → 1.52 m