Question

If 3 A current flows through an electric iron which is

designed to work at 230 V for 10 s, calculate heat energy

generated using the following equation .

H = (V 2 /R)t
​

Answer 1

Answer:

• Current=I=3A
• Voltage=V=230V
• Time=t=10s

First calculate the resistance

• Using ohms law

$\boxed{\sf \dfrac{V}{I}=R}$

$\\ \sf\longmapsto Resistance=\dfrac{230}{3}$

$\\ \sf\longmapsto Resistance=76.6\Omega$

Now

$\boxed{\sf H=\dfrac{v^2}{R}t}$

$\\ \sf\longmapsto Heat=\dfrac{230^2}{76.6}\times 10$

$\\ \sf\longmapsto Heat=\dfrac{52900}{766}$

$\\ \sf\longmapsto Heat=69.1J$