A current of 3 amp flows through the 2Ω resistor shown

Home » Electricity and Magnetism » Current Electricity » Question

A current of 3 amp flows through the 2Ω resistor shown in the circuit. The power dissipated in the 5-Ω resistor is:

1. 4 watt
2. 2 watt
3. 1 watt
4. 5 watt

Correct Option: D

Clearly, 2Ω , 4Ω and ( 1 + 5) Ω resistors are in parallel. Hence, potential difference is same across each of them.
∴ I₁ × 2 = I₂ × 4 = I₃ × 6

Given I₁ = 3A
∴ I₁ × 2 = I₃ × 6
Given I₁ = 3A.
∴ I₁ × 2 = I₃ × 6 provides

I₃ =	I₁ x 2	=	3 x 2	= 1A
	6		6

Now, the potential across the 5Ω resistor is V = I₃ × 5 = 1 × 5 = 5V.
∴ the power dissipated in the 5Ω resistor

P =	V²	=	5²	= 5 Watt.
	R		5