Question

Two appliances of rating 200 watt-250 volts and 100 watt-250 volts are joined in series to a 250 volts supply. Total power consumed in the circuit is ?​

Answer 1

For bulb 1

P = 200 watt

V = 250 V

I = P/V

I = 200/250

I = 0.8 A

R = V/I

R = 250/0.8

R = 312.5 ohm

For bulb 2

P = 100 watt

V = 250 V

I = P/V

I = 100/250

I = 0.4 A

R = V/I

R= 250/0.4

R = 625 ohm

Total resistance in circuit = 625 + 312.5

= 937.5 ohm

Total power consumed, P = V²/R

= 250 × 250/937.5

= 66.66 watt or 67 watt

Answer 2

Two bulbs marked 200 watt-250 volts and 100 watt-250 volts are joined in series to 250 volts supply. Power consumed in circuit is. A: 67 watt.