Question

14. An unknown resistance R, is connected in series with
a resistance of 10 . This combination is connected
to one gap of a metre bridge while a resistance R,
is connected in the other gap. The balance point
is at 50 cm. Now, when the 10 2 resistance is
removed the balance point shifts to
40 cm. The value of R, is (in ohms) :-​

Answer 1

An unknown resistance

is connected is series with a resistance of

. This combination is connected to one gap of a meter bridge, while other gap is connected to another resistance

. The balance point is at

Now , when the

resistance is removed, the balanced point shifts to

Then the value of

is.

Answer 2

Answer

20 Ω

Explanation

Method:Application of formula  

 

In first case,

R1+10/R2=50/100-50

or R1+10=R2

In second case,

R1/R2=40/100-60=2/3  

 

On solving, R1=20 ohms