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

Voltage across 2   Ω is the same as voltage across arm containing 1   Ω and 5   Ω resistances. Voltage across 2   Ω resistance,V=2  ×  3=6  VSo, voltage across lowest arm,V1 = 6 VCurrent across 5  Ω,  I=61+5  =1 AThus, power across 5   ΩP = I2 R = (1)2 x 5 = 5 W