Advertisements
Advertisements
Question
If an electric iron of 1200 W is used for 30 minutes every day, find electric energy consumed in the month of April.
Advertisements
Solution
Power of electric iron, P = 1200 W Time for which it is used in one day, t = 30 min
= 30 × 60 s
= 1800 s
Energy consumed in one day = P × t
= 1200 W × 1800 s
= 2.16 × 106 J
As there are 30 days in April, so energy consumed in the month of April = 2.16 × 106 × 30 J
= 6.48 × 107 J
APPEARS IN
RELATED QUESTIONS
State the energy changes in the following while in use An electric oven.
State the energy changes in the following while in use A loudspeaker .
State the energy changes that occur in the following :
The unwinding of a watch spring.
Energy can exist in several forms and may change from one form to another. State the energy changes that occur in a car going uphill.
Energy can exist in several forms and may change from one form to another. State the energy changes that occur in the Charging of a battery.
State the energy changes in the following case while in use:
Bio-gas burner
A boy is moving on a straight road against a frictional force of 5 N. After travelling a distance of 1.5 km he forgot the correct path at a roundabout (Fig. 11.1) of radius 100 m. However, he moves on the circular path for one and half-cycle and then he moves forward up to 2.0 km. Calculate the work done by him.
Four men lift a 250 kg box to a height of 1 m and hold it without raising or lowering it.
(a) How much work is done by the men in lifting the box?
(b) How much work do they do in just holding it?
(c) Why do they get tired while holding it? (g = 10 m s–2)
Define watt. Express kilowatt in terms of joule per second. A 150 kg car engine develops 500 W for each kg. What force does it exert in moving the car at a speed of 20 ms–1?
For burning of coal in a thermoelectric station, the energy conversion taking place is:
