A 10m long wire of uniform cross-section and 20ohm resistance used in a potentiometer. This wire is connected in series with a battery of 5 V

Q. A 10m long wire of uniform cross-section and 20ohm resistance used in a potentiometer. This wire is connected in series with a battery of 5 V along with an external resistance of 480Ω. If an unknown e.m.f. E is balanced at 6.0m length of the wire, then the value of unknown emf is-

(i) 1.2 V
(ii) 1.02 V
(iii) 0.2 V
(iv) 0.12 V

Answer: (iv) 0.12 V

Let PQ is a potentiometer wore of length 10m,

If 10 m potentiometer wire balances =0.2 V

Then 1 m potentiometer wire balances =0.2/10V

Then 6 m potentiometer wire balances

error: Content is protected !!