Question

A 10 m long potentiometer wire has a resistance of 20 ohm. It is connected in series with a battery of emf 3V and a resistance of 10 Ω The internal resistance of cell is negligible. If the length can be read accurately up to 1 mm, the potentiometer can read voltage.

(A) up to minimum of 0.2 mV 

(B) with an accuracy of 0.2 mV 

(C) with an accuracy of 0.1 mV 

(D) up to maximum of 2V

Answer 1

Correct option: (B, D)

Explanation:

Current in wire = 3/30 = 0. 1 A

maximum voltage can read = 2V

least account of scale = 1 mm

accuracy = 0.2 mV.