Calculating Heat Flow in Electric Iron
The problem asks for the heat generated by an electric iron given its resistance, current, and the time duration.
Given Data:
- Resistance, $R$ = 20 ohm
- Current, $I$ = 5 A
- Time, $t$ = 30 s
Formula Used:
The heat generated by an electrical appliance is calculated using Joule's law of heating:
$H = I^2 R t$
Where:
- $H$ is the heat generated (in Joules, J)
- $I$ is the current flowing (in Amperes, A)
- $R$ is the resistance (in Ohms, $\Omega$)
- $t$ is the time (in Seconds, s)
Calculation:
Substitute the given values into the formula:
$H = (5\text{ A})^2 \times (20\ \Omega) \times (30\text{ s})$
First, calculate the square of the current:
$I^2 = (5)^2 = 25\text{ A}^2$
Now, multiply this by the resistance and time:
$H = 25\text{ A}^2 \times 20\ \Omega \times 30\text{ s}$
$H = 500 \times 30\text{ J}$
$H = 15000\text{ J}$
Expressing this in scientific notation:
$H = 1.5 \times 10^4\text{ J}$
Result:
The heat flow in 30 seconds is $1.5 \times 10^4\text{ J}$.
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