Question

How much is the heat energy produced in $10seconds$ in an electric iron having resistance $440\Omega$, when a potential difference of $220volt$ is applied across it?

• A. $600J$
• B. $1100J$
• C. $300J$
• D. $1500J$

Answer 1

The correct option is B $1100J$

According to joule's law of heating, heat produced in a resistor $\left(R\right)$ is given by, $H=I^2\times R\times t$
when current $\left(I\right)$ flows through the resistor for time $\left(t\right)$

The amount of current through the electric iron having resistance$\left(R\right)$ $440\Omega$ when connected to potential difference$\left(V\right)$ of $220volt$ is given by:

$I=\frac{V}{R}=\frac{220}{440}=0.5A$ (ohm's law)

So, heat produced in electric iron is:

$H=I^2\times R\times t$
$=(0.5A{)}^2\times 440\Omega \times 10s=1100J$