Question

The resistance of each arm of the wheat stone bridge is $10\Omega$. A resistance of $10\Omega$ is connected in series with galvanometer then the equivalent resistance across the battery will be :-

• A. $10\Omega$
• B. $15\Omega$
• C. $20\Omega$
• D. $40\Omega$

Answer 1

The correct option is A $10\Omega$

Here, $P=Q=S=R=10\Omega$
since $\frac{P}{Q}=\frac{S}{R}=1,$ so it is balanced Wheatstone bridge and no current pass through galvanometer.
As all arm resistances are equal so its equivalent resistance is also $10\Omega$.