AP EAMCET Engineering 22 Apr 2019 Shift 1 Paper

The meter bridge is shown below,The equivalent resistance of

n

2

series resistances is,
Req=R1+R1+.....

n

2

times
Req=

nR1

2

The equivalent resistance of

n

2

parallel resistances is,
R′eq=

1

R1

+

1

R1

+.....

n

2

times
R′eq=

n

2R1

If l be the balancing length in the meter bridge wire, then,

Req

R′eq

=

l

100−l

( nR1 2 )

( 2R1 n )

=

l

100−l

n2

4

=

l

100−l

l=

100n2

n2+4