In the netwrok shown in fig. each resistance is R.

The equivalent resistance between A and B is

Options

A. `(3R)/(4)`
B. `(5R)/(6)`
C. `(7R)/(12)`
D. `(4R)/(3)`

Answer

C

Explanation

If we connect a battery across A and
B, then E and D will be at the same
potential and F and C will be at the
same potential.

`R_(eq)(AB) = (7R)/(12)`
If we connect the battery across A
and G, the B, E, and D will be at
the same potential. C,F, and H will
be at the same potential.

If we connect the battery across A and C, then no current will flow in
the resistances between B and F and between H and D. So they can
be removed. Thus,
`R_(eq) = (3R)/(4)`