An electric iron rated 750 W is operated for 2 hours/day. How much energy is consumed by the electric iron for 30 days?
An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be ______.
What is consumed using different electrical appliances, for which electricity bills are paid?
Name the quantity whose unit is (i) kilowatt, and (ii) kilowatt-hour.
What is the maximum power in kilowatts of the appliance that can be connected safely to a 13 A ; 230 V mains socket?
How many joules are there in one kilowatt-hour?
The commercial unit of energy is :
(a) watt
(b) watt-hour
(c) kilowatt-hour
(d) kilo-joule
Explain why, filament type electric bulbs are not power efficient.
An electric bulb is rated ‘100 W, 250 V’. What information does this convey?
Two lamps, one rated 220 V, 50 W and the other rated 220 V, 100 W, are connected in serieswith mains of 220 V. Explain why does the 50 W lamp consume more power
State the position of heating element with respect to principal focus of concave reflector and give reason for choosing this position.
Why is the heating element of an electric oven wound on a helix? State the reason.
Two electric lamps each rating 100 W, 110 V are connected in series to a 220 V power supply and two other electric lamps each of marking 100 W, 220 V are connected in parallel to the same power supply. Will anyone of the two combinations give more light than the other? Give a reason for your answer.
Three 250 W heaters are connected in parallel to a 100 V supply, Calculate the energy supply in kWh to the three heaters in 5 hour.
State (i) the S. I. unit, (ii) the household unit, of electrical energy. How are these units related?
An Electric bulb is marked 100 W, 230 V. What current does it take?
The equation I2R seems to suggest that the rate of heating in a resistor is reduced if resistance decreases, whereas equation P = V2/R suggests just the opposite. How do you reconcile this problem?
Two resistances R1 = 4Ω and R2 = 6Ω are connected in series. The combination is connected with a battery of e.m.f. 6V and negligible resistance. Calculate:
(i) the heat produced per minute in each resistor,
(ii) the power supplied by the battery.
An immersion rod having resistance of 50 Ω is connected to 220V main supply. Assuming that all the energy generated goes to heat the water, calculate the time taken to heat 5 kg water from 30°C to 100°C.
