Question

A potential difference of 220v is applied across a resistance of 440 ohm in a electrical appliance. Calculate the current drawn and the heat energy produced in 20 seconds

Answer 1

1/2 by using homes law

Answer 2

By using the Ohm's Law we can find the current drawn,

V = IR --------------(1)

V - Potential Difference

I - Current

R - Resistance

220 = I x 440

I = 1/2 A

And also we wanted to recall the below equations related to power (P) dissipated from a resistor,

$P=IV$

$P = V^{2}/R$

$P=I^{2} R$

We can derive above equations by using equation (1)

I am using $P=IV$ to find the heat energy,

$Pt = VIt$

Dissipated Heat Energy = 220 x 1/2 x 20

Dissipated Heat Energy =2200 J