Question

A bulb is rated 5.0 volt 100ma . Calculate its rated power and resistance.

Answer 1

P = V I = 5.0 * 100E-3 = 500E-3 W or 0.50 watts  

R = V/I = 5.0 / 0.100 = 50 ohms

Answer 2

1000mA = 1A

So, 100mA = 100/1000 = 0.1A

Potential difference = 5V (given)  

Resistance = V/I = 5/0.1 = 50 Ohm

Power = I x I x R = 0.1 x 0.1 x 50 = 0.5 Watt.

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