Advertisements
Advertisements
Question
Solution
Electrical power is defined as the rate at which energy is changed or work is done i.e., the work done per second or energy converted per second.
Electrical appliances come with certain number of watts and volts written on them. Power rating of an electrical appliance gives the knowledge of the safe current limit of an appliance and also indicates the voltage above which the appliance should not be used.
APPEARS IN
RELATED QUESTIONS
State two factors on which the electrical energy consumed by an electrical appliance depends.
Which one has a higher electrical resistance : a 100 watt bulb or a 60 watt bulb?
Define 1 kilowatt hour.
A coil of copper wire is connected to a galvanometer. What would happen if a bar magnet is:
(i) Pushed into the coil with its north pole entering first?
(ii) Held at rest inside the coil?
(iii) Pulled out again?
What is electric power? State and define its S.I. unit.
What is the function of the split rings in a d.c. motor?
With reference to the diagram shown below calculate:
(i) The equivalent resistance between P and Q.
(ii) The reading of ammeter.
(iii) The electrical power between P and Q.
The following table gives the electrical appliances used, their power and the average time for which they are used each day in a home. Estimate the monthly electricity bill if the rate is 60 paise per unit.
Sr.no. | Name | Nos. | Power rating | Time/day |
1 | Bulb | 4 | 100 W | 7.5 hr |
2 | Fans | 2 | 50 W | 10 hr |
3 | T.V. | 1 | 100 W | 2 hr |
4 | Iron | 1 | 500 W | 1 hr |
5 | Electric stove | 1 | 750 W | 2 hr |
Electric power is inversely proportional to ____________.
A student wants to use an electric heater, an electric bulb and an electric fan simultaneously.
How should these gadgets be connected with the mains? Justify your answer giving three reasons.