Find the resistance of a cube of edge $60 \text{ cm}$,made of a material of specific resistance $60 \times 10^{-8} \Omega \text{ m}$.

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 the 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 a function of the strain $\varepsilon$ when the strain is small? Neglect Joule heating.

$A$ wire of resistance $5 \Omega$ is stretched so that its new length is $3$ times its original length. What is the resistance of the new wire?

Why does the resistivity of metals increase with an increase in temperature?

The electrical resistance of an iron wire is $R$. If both its length and radius are doubled,then:

At room temperature $(27^\circ \text{C})$ the resistance of a heating element is $100 \ \Omega$. What is the temperature of the element if the resistance is found to be $137 \ \Omega$,given that the temperature coefficient of the material of the resistor is $1.35 \times 10^{-4} \ ^\circ \text{C}^{-1}$ (in $^\circ \text{C}$)?