Question

The potentiometer wire AB shown in the figure (32-E26) is 40 cm long. Where should the free end of the galvanometer be connected on AB, so that the galvanometer may show zero deflection?
Figure

Answer 1

Answer:

the answer will be 64-E52

Answer 2

Explanation:

On AB potentiometer wire, the galvanometer’s free end is connected. Let the potentiometer’s null point be taken as D. At the interaction as the bridge is at stability of contact, then

RADRDB = 812

According to the potentiometer principle,

RADRDB = lADlDB = 812 ⇒lAD = 23lDBlAD + lDB

⇒lDB23+ lDB = 40 cm

⇒53lDB = 40 cm

⇒lDB = 35 $\times$ 40 = 24 cm

Hence, the obtained null-point from B is 24 cm.