Question

An electric iron of resistance 30 ohm takes a current of 4A
Caluclate the heat devloped in 50 sec.
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Answer 1

Given :

• Resistance =30ohm

•current =4 A

• Time=50seconds

To Find :

• Heat developed in 50 seconds=?

Solution :

The amount of heat (H) produced is given by joules law of heating as H=VIT

where, R=30ohm

current ,I=4A

Time, T=50seconds

$\\ \implies \sf \: voltage = current \times resistance \: \\ \\ \implies \sf \: voltage = 5 \times 20 \\ \\ \implies \boxed{ \sf{voltage = 100 \: volt}}$

$\\ \implies\sf{H=VIT}$

$\\ \implies\sf{H=100 \times 4 \times 50}$

$\\ \implies\sf{H=2\times 10^{4}}$

$\\ \implies\boxed{\sf{Heat(H)=2 \times 10^{4}}}$

Therefore, the amount of heat developed in

the electric iron is $\rm{2 \times 10^{4}}$

Additional information :

1. Ohm's Law : According to this law, applied voltage is directly proportional to the resistance.
2. The unit of resistance is ohm

$\red\bigstar\boxed{\sf{Applied \: voltage(V) =IR}}$