Question

For a constant resistance, the correct relation between heat produced (H) and electric current (I) flowing is:

• A. $\text{H}\propto \text{I}$
• B. $\text{H}\propto {\text{I}}^{-1}$
• C. $\text{H}\propto {\text{I}}^2$
• D. $\text{H}\propto {\text{I}}^{-0.5}$

Answer 1

The correct option is C $\text{H}\propto {\text{I}}^2$

According to Joule's law, the heat produced in a resistor is;
(i) directly proportional to the square of current for a given resistance.
(ii) directly proportional to resistance for a given current.
(iii) directly proportional to the time for which the current flows through the resistor.
That is $H=I^2\times R\times t$
Hence $H\propto I^2$ is the right relation.