Question

When a high resistance voltmeter is connected directly across a resister its reading is 2 V. An electric cell is sending the current of 0.4A, (measured by an ammeter) in the electric circuit in which a rheostat is also connected to vary the current.
Draw an equivalent labelled circuit for the given data.

Answer 1

Explanation:

Since the voltmeter reading shows 2V. Thus V = 2.

Also, Current send by electric cell = 0.4A

Thus I = 0.4A

By Ohm’s law V = IR

⇒ 2 = 0.4 × R

⇒

The resistance of the resistor is 5Ω.

Answer 2

Resistance of the resistor is 5Ω

Explanation:

Given: Reading in the Voltmeter is 2V. So V = 2

Reading in the Ammeter is 0.4 A. So I = 0.4

According to Ohm’s Law, we know that V = IR

So 2 = 0.4 * R

R = 2/ 0.4 = 5 Ohms.

Resistance of the resistor is 5Ω.

Please find the attached picture for the circuit diagram with Voltmeter, Ammeter, Rheostat and batteries.