Question

Five resistors each of value m are connected between points A and F as shown in figure. If two similar wires are connected one between points B and D another between points C and E. The effective resistance between points A and F will be

• A. 7 m
• B. 5 m
• C. 3 m
• D. 6 m

Answer 1

The correct option is C 3 m

If two resistors are added

There is a balanced Wheatstone bridge, so equivalent circuit becomes as shown in fig (2). These dotted resistors are in series

So equivalent circuit becomes as shown in fig (3). 2M resistors are in parallel, So equivalent circuit becomes as shown in fig (4)

Net resistance = $m+m+m$

=$3m$