States Joule's law of heating and give its expression.

As shown in the schematic below, a rod of uniform cross-sectional area $A$ and length $l$ is carrying a constant current $i$ through it and voltage across the rod is measured using an ideal voltmeter. The rod is stretched by the application of a force $F$.

Which of the following graphs would show the variation in the voltage across the rod as function of the strain $\epsilon$ when the strain is small. Neglect Joule heating.

In the circuit shown, the heat produced in $5 \mathrm{\Omega }$ resistor is $10 \mathrm{cal} {\mathrm{s}}^{-1}$. The heat produced per sec in $4 \mathrm{\Omega }$ resistor will be

Verification of joule's law of heating​.

Two identical immersion heaters are to be used to heat water in a large container. Which one of the following arrangement would heat the water faster;

(i) connecting the heaters in series with the main supply,

(ii) connecting the heaters in parallel with the main supply?

Represent the union of two sets by Venn diagram for each of the following.

$X=\{x | x$ is a prime number between $80$ and $100\}$

$Y=\{y | y$ is an odd number between $90$ and $100\}$

State joules law of heating ? Write any two applications of heating effect of electric current​.