Question

a 100 W 220V bulb is connected across 110 V supply. the actual power consumed by the bulb will be ?​

Answer 1

Answer: POWER = 25W

Explanation:

GIVEN:    Power of bulb = 100W           Voltage of bulb = 220V .

FORMULA = power =        (voltage)²

                                         resistance

let us find Resistence = X ohm

on substituting ,

           ⇒         100W =      (220)²  

                                        X ohm

            ⇒        100 = 48400 / x ohm

            ⇒       484 = x ohm

now let us find power = Y Watt

Voltage of supply = 110V   ,    Resistance of bulb = 484 ohm

            ⇒ Y Watt =  (110)² /  484

            ⇒ Y =  12100 / 484

                  ∴ power consumed will be=  25W