Question

In the following figure, what is the value of I?

(a) I = IV + Ir

(b) I = IV – Ir

(c) I = IV Ir

(d) I = ^IV ⁄ Ir

I had been asked this question in a national level competition.

This interesting question is from Measurement of Low Resistance in portion Measurement of Resistance of Electrical Measurements

Answer 1

The correct choice is (a) I = IV + Ir

To explain: By applying Kirchhoff’s current law at the node N from fig we get,

I = IV + Ir

where,

I is the total series current flowing through the circuit

Iv is the current flowing through the voltmeter

Ir is the current flowing through the resistance R.