Sunil Batra Solutions for Chapter: Electricity, Exercise 3: Practice Exercise 1C

A lamp rated $100 \mathrm{W}$ at$220 \mathrm{V}$ is connected to the mains electric supply. What current (in ampere) is drawn from the supply line if the voltage is $220 \mathrm{V}$?

Calculate the electric energy (in $\mathrm{kWh}$) consumed by a $1200 \mathrm{W}$ toaster in $20$ minutes.

Write the formula for the amount of heat ($H$) produced in a resistor ($R$) when current ($I$) flows through it for time ($t$). Give three applications of heating effect of current.

Define power. Give its S.I. unit and define it.

A current of$5 \mathrm{A}$flows through a $12 \Omega$resistor. What is the rate at which heat energy (in watt) is produced in the resistor?

An electric bulb is rated $220 \mathrm{V}- 60 \mathrm{W}$. Calculate its resistance. If four such bulbs are used for four hours what is the electrical energy consumed? Calculate the cost if the rate per unit is ₹ $4.80$.

Two coils of resistances $5 \Omega$and $10 \Omega$ are connected across a battery of emf $10 \mathrm{V}$. Find the electrical energy consumed in $5$ minutes by each coil when,
(a) these are connected in parallel
(b) these are connected in series.

In a household four undefined electric bulbs are lighted for $2$ hours and two undefinedbulbs are lighted for $4$ hours every day. Calculate the energy consumed in the house for undefinedday. Calculate the electricity bill if it is charged as ₹undefined