Question

In a Wheatstone's bridge all the four arms have equal resistance R. If the resistance of the galvanometer arm is also R, the equivalent resistance of the combination as seen by the battery is :

Answer 1

Answer:

On a Wheatstone's bridge all the four arms have equal resistance R. If the resistance of the galvanometer arm is also R, the equivalent resistance of the combination as seen by the battery is R.

Explanation:

In balanced condition of Wheatstone's bridge there will be no current flowing through the arms BD.

Hence the equivalent resistance of the combination is seen by the battery is R.

Answer 2

Answer:

The correct answer is'R'

Explanation:

As all the four arms have equal resistance R so it is a balanced (P/Q=R/S) Wheatstone bridge circuit. Thus, no current flow in the galvanometer arm and its resistance will not working. So the corresponding circuit is shown in figure.

The equivalent resistance is R

AB =

(R+R)+(R+R)

_________

(R+R)(R+R)

=4R

2

/4R=R