Advertisements
Advertisements
प्रश्न
An electric motor takes 5 amperes current form a 220 volt supply line. Calculate the power of the motor and electric energy consumed by it in 2 hours.
Advertisements
उत्तर
Given:
I = 5 A
V = 220 V
Power of the motor,
P = VI
=` 5 xx 220`
= 1100 W = 1.1 kW
Energy consumed in two hours,
E`= pxxt`
= `1.1 kW xx 2 h`
= 2.2 kWh
APPEARS IN
संबंधित प्रश्न
An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be ______.
Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?
In a house two 60 W electric bulbs are lighted for 4 hours, and three 100 W bulbs for 5 hours everyday. Calculate the electric consumed in 30 days.
At a given time, a house is supplied with 100 A at 220 V. How many 75 W, 220 V light bulb could be switched on in the house at the same time (if they are all connected in parallel)?
State whether an electric heater will consume more electrical energy or less electrical energy per second when the length of its heating element is reduced. Give reasons for your answer.
Distinguish between kilowatt and kilowatt-hour.
Two bulbs are rated 60 W, 220 V and 60 W, 110 V respectively. Calculate the ratio of their
resistances
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.
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.
Give two precautious that you would take while putting off an electric switch.
An electric heater is rated 220 V, 550 W. Electrical energy is also measured in kWh. What do you understand by a kilo-watt-hour?
How can electric energy consumed by an electric appliance be calculated in kilowatt hour (kWh)?
An Electric bulb is marked 100 W, 230 V. What how long would this lamp take to consume one unit of electricity?
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.
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.
Unit of electric power may also be expressed as:
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.
1 kWh = ______ J.
