Embibe Experts Solutions for Exercise 1: EXERCISE

Two wires $A$ and $B$ of circular cross-section are made of the same metal and have equal lengths, but the resistance of wire $A$ is four times greater than that of wire $B$. Find the ratio of their cross-sectional areas.

A sphere of radius $10 \mathrm{mm}$ that carries a charge of $8 \mathrm{nC}=8\times {10}^{-9}\mathrm{C}$ is attached at the end of an insulating string and is whirled in a circle. The rotation frequency is $100\mathrm{\pi } \mathrm{rad} {\mathrm{s}}^{-1}$.

(a) What is the basic definition of current in terms of charge?

(b) What average current does this rotating charge represent?

A $2$ ampere current flows in a uniform conductor which has $1\times {10}^{24}$ free electrons per metre. What is their average drift velocity?

A $2$ ampere current flows in a uniform conductor which has $1\times {10}^{24}$ free electrons per metre. What is their average drift velocity?

If the circuit is a $20$ feet long wire in your automobile, approximately how long would it take an electron to travel from the negative terminal to the positive terminal of the battery?

Two copper wires have the same length but the second has diameter twice that of the first. If the resistance of the first is $2$ ohms, the resistance of the second is

A wire of resistance $R$ and of radius $r$ is compressed back to another wire of radius $2 \mathrm{r}$, the new resistance of the wire will be