Question

Four resistances of 15 $\Omega$, 12 $\Omega$, 4 $\Omega$ and 10 $\Omega$ respectively in cyclic order to form Wheatstone's network. The resistance that is to be connected in parallel with the resistance of 10 ft to balance the network is __________ $\Omega$.

Answer 1

Answer: 10.00

Let the resistance to be connected is R.
For balanced wheatstone bridge,
$15\times 4=12\times \frac{10R}{10+R}$
$\Rightarrow R=10\Omega$