In an electrical circuit two resistors of 2 Ω and 4 Ω respectively

In an electrical circuit two resistors of 2 Ω and 4 Ω respectively are connected in series to a 6 V battery. The heat dissipated by the 4 Ω resistor in 5 s will be

  1. 5 J
  2. 10 J
  3. 20 J
  4. 30 J

Answer

Here, first resistor, R1 = 2 Ω

Second resistor, R2 = 4 Ω

Voltage of cell, V = 6 V

Time taken = t = 5 s

Total resistance of the circuit = R = R1 + R2 = 2 + 4 = 6 Ω

Current, I = V/R = 6/6 = 1 A

Heat dissipated by the 4 Ω resistor in 5 s is given as,

H = I2Rt

H = 1 × 4 × 5 = 20 J

The correct option is C.