In the given circuit of potentiometer, the potential difference E across AB ( length) is larger than and as well. For key (closed), the jockey is adjusted to touch the wire at point so that there is no deflection in the galvanometer. Now the first battery () is replaced by the second battery () for working by making open and closed. The galvanometer gives then null deflection at . The value of is the smallest fraction of , Then the value of is ____.
Step 1: Find the balancing length from end A, when is closed and
Length of
For battery , the balancing length is
For key (closed), the jockey is adjusted to touch the wire at point so that there is no deflection in the galvanometer, that is balancing length is
Step 2: Find the balancing length from end A when is closed.
For battery , the balancing length is
For key (closed), the jockey is adjusted to touch the wire at point so that there is no deflection in the galvanometer, which is balancing at .
Step 3: Find the value of is the smallest fraction of
Know that
Equating with the smallest fraction, the value of a would-be
Therefore, the correct answer is 1.