Question

A torch bulb is rated as 4.5V ,200 mA. Its power is
1. 2.25 W
2. 4.4 W
3. 0.9 W
4. 9 W

Answer 1

Correct Answer - Option 3 : 0.9 W

CONCEPT :

• The electrical power is the product of voltage and current and is it written as

⇒ P = VI

Where V = Voltage , I = Current 

CALCULATION :

Gicen - V = 4.5 V, I  = 200 mA = 200 × 10^-3A

• The power of electrical appliance is given by

⇒ P = 200 × 10^-3 × 4.5 = 900 × 10^-3 = 0.9 W

• Hence, option 3 is the answer