Advertisements
Advertisements
Question
An Electric bulb is marked 100 W, 230 V. What current does it take?
Advertisements
Solution
Current flowing in bulb = i = `"P"/"V"`
`= 100/230 = 10/23 "A" = 0.435` A
APPEARS IN
RELATED QUESTIONS
Which uses more energy: a 250 W TV set in 1 hour or a 1200 W toaster in 10 minutes?
What is the maximum power in kilowatts of the appliance that can be connected safely to a 13 A ; 230 V mains socket?
Why is an electric light bulb not filled with air? Explain why argon or nitrogen is filled in an electric bulb.
Name the S.I. unit of electrical energy. How is it related to Wh?
An electric bulb marked 220 V, 100 W will get fused if it is made to consume 150 W or more. What voltage fluctuation will the bulb withstand?
The diagram below shows a magnetic kept just below the conductor AB which is kept in North South direction.

(i) In which direction will the needle deflect when the key is closed ?
(ii) Why is the deflection produced ?
(iii) What will be the change in the deflection if the magnetic needle is taken just above the conductor AB ?
(iv) Name one device which works on this principle.
Fig . shows the essent ial features of a battery operated bell. The hammer strikes the gong when the swi tch is closed . State and explain the effect of using the following material successively to form the core.

(a) Plastic
(b) Steel
(c) Copper
Out of the three fuses with current ratings 5A, 10A, 15A, which one is to be connected in a geyser circuit marked 3 kW, 220V? Give reason for your answer.
An electric appliance is rated at 1000 W, 250V. Calculate:
(i) The electrical energy consumed by the appliance in 12 hour.
(ii) The cost of energy consumed at Rs. 1.20 per kWh.
How long would this appliance take to use 1 kWh energy when operated at 250 V?
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 |
