A metal rod of length $10 \mathrm{cm}$ and a rectangular cross-section of $1 \mathrm{cm}\times \frac{1}{2} \mathrm{cm}$ is connected to a battery across opposite faces. The resistance will be

If the last band on the carbon resistor is absent, then the tolerance is

$I-V$ characteristic of a copper wire of length $L$ and area of cross-section $A$ is shown in figure. The slope of the curve becomes

$\mathrm{I} - \mathrm{V}$ graphs for two different electrical appliances $P$ and $Q$ are shown in the diagram. If ${\mathrm{R}}_{\mathrm{P}}$ and $R_{\mathrm{Q}}$ be the resistances of the devices, then