Question

1 ohm resistance is in series with a Ammeter which is balanced by 75 cm of potentiometer wire. A standard cell of 1.02 V is balanced by 50 cm.t he ammeter shows a reading of 1.5 A. The error in the ammeter reading is

Answer 1

Thus the error in the ammeter reading is 0.03 A

Explanation:

In potentiometer:

V ∝ R ∝ l

= > V ∝ l

=> V1 / V2 = l1 / l2 = 75 / 50 = 3 / 2

= > V1 = 1.5 x 1.02 = 1.53 V

I1 = V1 / R1 = 1.53 / 1 = 1.53 A

Error = 1.53 - 1.50 = 0.03 A

Thus the error in the ammeter reading is 0.03 A