Question

The potentiometer wire AB shown in the figure (32−E27) is 50 cm long. When AD = 30 cm, no deflection occurs in the galvanometer. Find R.
Figure

Answer 1

The value of R in this scenario is 4 Ω.

Explanation:

In the galvanometer, there is no deflection in the given point D, which is the balance of the bridge. This is shown as below:

⇒RADRDB = 6R

As per the potentiometer’s principle,  

lADlDB = RADRDB ⇒6R = 30 20 ⇒R = 20 $\times$ 630 = 4 Ω

So, the scenario’s f value of R is given as 4 Ω.