Lakhmir Singh and Manjit Kaur Solutions for Chapter: Electricity, Exercise 32: Short Answer Type Questions

An electric motor takes $5 \mathrm{amperes}$ current from a $220 \mathrm{volt}$ supply line. Calculate the power of the motor and electrical energy consumed by it in $2 \mathrm{hours}$.

Which uses more energy: a $250 \mathrm{W}$ TV Set in $1 \mathrm{hour}$ or a $1200 \mathrm{W}$ toaster in $10 \mathrm{minutes}$?

Calculate the power used in the $2 \mathrm{\Omega }$ resistor in each of the following circuits:
(i) a $6 \mathrm{V}$ battery in series with $1 \mathrm{\Omega }$ and $2 \mathrm{\Omega }$ resistors.
(ii) a $4 \mathrm{V}$battery in parallel with $12 \mathrm{\Omega }$ and $2 \mathrm{\Omega }$ resistors.

Two lamps, one rated $40 \mathrm{W}$ at $220 \mathrm{V}$ and the other $60 \mathrm{W}$ at $220 \mathrm{V}$, are connected in parallel to the electric supply at $220 \mathrm{V}$.
(a) Draw a circuit diagram to show the connections.
(b) Calculate the current drawn from the electric supply.
(c) Calculate the total energy consumed by the two lamps together when they operate for one $\mathrm{hour}$.

An electric kettle connected to the $230 \mathrm{V}$ mains supply draws a current of $10 \mathrm{A}$. Calculate:
(a) the power of the kettle.
(b) the energy transferred in $1 \mathrm{minute}$.

A $2 \mathrm{kW}$ heater, a $200 \mathrm{W}$ TV and three $100 \mathrm{W}$ lamps are all switched on from $6 \mathrm{pm} \mathrm{to} 10 \mathrm{pm}$. What is the total cost at $₨5.50$ per $\mathrm{kWh}$?

What is the maximum power in $\mathrm{kilowatts}$ of the appliance that can be connected safely to a $13 \mathrm{A}, 230 \mathrm{V}$ mains socket?

An electric fan runs from the $230 \mathrm{V}$ mains. The current flowing through it is $0.4 \mathrm{A}$. At what rate is electrical energy transferred by the fan?