If power dissipated in the 9-Ω resistor in the circuit

If power dissipated in the 9-Ω resistor in the circuit shown is 36 watt, the potential difference across the 2-Ω resistor is

We have,

P =	V²
	R

⇒ 36 =	V²
	9

⇒ V = 18V
Current passing through the 9Ω resistor is

i₁ =	V	=	18	= 2A
	R		9

The 9Ω and 6 Ω resistors are in parallel, therefore

i₁ =	6	x i
	9 + 6

where i is the current delivered by the battery.

∴ i =	2 x 15	= 5 A
	6

Thus, potential difference across 2Ω resistor is
V = iR
= 5 × 2
= 10V