Question

Calculate the heat developed when 3A current flows through an electric iron box designed to work under 230V for 5 minutes?

Answer 1

Answer:

2,07,000 joules

Explanation:

heat = i×v×t

230×3×300 time in seconds

=2,07,000 joules

Answer 2

Need to FinD :-

• The heat developed in the iron box .

$\red{\frak{Given}}\begin{cases}\sf Current ( I ) = 3A \\\\\sf Voltage = 230V \\\\\sf Time = 5\ min = 1800s.\end{cases}$

We know that the heat developed in a circuit is ,

• Directly proportional to the square current flowing through it .
• Directly proportional to the Resistance of the circuit .
• Directly proportional to the time of flow of the current.

Therefore ,

$\\\\\footnotesize\sf\longrightarrow \red{ H= I^2RT }$

Also , by Ohm's Law,

$\\\\\footnotesize\sf\longrightarrow \red{ V = IR }$

From above two , we get ,

$\\\\\footnotesize\sf\longrightarrow H= I * I R * T \\\\\\\footnotesize\sf\longrightarrow H = V * I * T$

• Put on the respective values ,

$\\\\\footnotesize\sf\longrightarrow H= 3A * 230V *5min \\\\\\\footnotesize\sf\longrightarrow H = 3A * 230V * 5 * 60 * 60s \\\\\\\footnotesize\sf\longrightarrow \underline{\underline{\red{ Heat = 12,42,000 \ Joules }}}$