Current Electricity — Prelims Questions

A wire of resistance $R$ is cut into five equal pieces. These five pieces are then connected in parallel. If the equivalent resistance of this combination is $R'$, then the ratio $R/R'$ is:

A cell of EMF $2\,\text{V}$ and internal resistance $0.5,\Omega$ is connected across a resistor of $3.5,\Omega$. The terminal potential difference across the cell is:

Two wires A and B of the same material have their lengths in the ratio $1:2$ and radii in the ratio $2:1$. The ratio of their resistances $R_A:R_B$ is:

Three resistors, $2,\Omega$, $3,\Omega$, and $6,\Omega$, are connected in parallel. The equivalent resistance of the combination is:

A $100\,\text{W}$, $220\,\text{V}$ bulb is connected to a $110\,\text{V}$ supply. The power consumed by the bulb will be:

In a Wheatstone bridge, the four arms have resistances $P=10,\Omega$, $Q=20,\Omega$, $R=15,\Omega$, and $S=30,\Omega$. A galvanometer is connected across the bridge. If the bridge is balanced, what is the current through the galvanometer?

The resistance of a conductor is $R$. If its length is doubled and its cross-sectional area is halved, its new resistance will be: