Question

(c) A lamp is marked 15 V, 30 W. How many joule does it consume in one hour and what is
the current that passes through it?​

Answer 1

Answer:

2 joule f current passes through it

Answer 2

Joule consumed in one hour and current that passes through it is :

• Given : Voltage = 15 V,

Power = 30 W = 30×10^-3 kW

• Energy = Power × Time

It is given in kilowatt per hour or watt per sec

• Energy is defined as the power consumed by all the appliances in one hour.

• Energy = 30×10^-3 kW × 1 hour = 0.03 J or kWH

• For current,

we know that, P = V^2 / R

where R = resistance

R = V^2 / P = 15×15 / 30 = 15/2 = 7.5 ohm

• Current, I = V / R = 15 / 7.5 = 2 A