Question

A current is passing through a resistor for a certain time. The current is doubled and the resistance halved while the time remains the same. What happens to the heating effect?

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Answer 1

Solution:

Step 1:-Let the original current = I amperes

Let the original resistance = R Ohms

Let the original time = t sec

Step 2:- Then we have

$H_1$ = $I_1$ Rt .......(1)

Now I, changes to 2I, R to $\frac{R}{2}$

While t remains the same.

What is H?

Step 3:- H = ${\left(2I\right)}^2$ .($\frac{R}{2}$) t J

= 2 $I^2$ Rt J............................(2)

Comparing (2) with (1), you find that (2) is double (1)

The heating effect is doubled.