QUESTIONS

An electric motor of $1 \mathrm{HP}$ (horse-power) is running at $220 \mathrm{V}$ What is the current in the motor? 

Calculate the equivalent resistance between points $A$ and $B$ in each of the following networks of resistors.

Calculate the equivalent resistance between points $A$ and $B$ in each of the following networks of resistors.

A wire whose resistance $0.1 \mathrm{\Omega }/\mathrm{cm}$, is bent in the form of a square $ABCD$ of side $10 \mathrm{cm}$.  An exactly similar wire is connected across the points $B$ and $D$. What will be the equivalent resistance between the other two corners$A$ and $C$ of the square? If a $2\mathrm{V}$ battery be connected between $A$and $C$, then what will be the current drawn from the battery? If an ammeter be connected across B and D. what will it read?

The resistance of a silver wire at $0°C$ is $1.25 \Omega$. Up to what temperature it must be heated so that its resistance is doubled? The temperature coefficient of resistance of silver is $0.00375°{\mathrm{C}}^{-1}$. Will the temperature be the same for all conductors of silver?

The resistance of the coil used in a platinum-resistance thermometer at $0°\mathrm{C}$ is $3.00 \mathrm{\Omega }$ and at $100°\mathrm{C}$ is $3.75 \mathrm{\Omega }$. Its resistance at an unknown temperature is measured $3.15 \mathrm{\Omega }$. Calculate the unknown temperature.

The resistance of a carbon filament at $0°\mathrm{C}$ is $104 \Omega$. What should be the resistance of an iron filament which should be connected in series with the carbon filament so that the resistance of the combined filament does not change with temperature? The temperature coefficient of resistance of iron is $\alpha =+ 0.0052°C^{-1}$ and of carbon is $-0.0003°{\mathrm{C}}^{-1}$.

A metallic wire has a resistance of $3.0 \Omega$ at $0°C$ and $4.8 \Omega$ at  ${150}^0 C$. Find the temperature coefficient of resistance of its material.