Advertisements
Advertisements
प्रश्न
Which uses more energy: a 250 W TV set in 1 hour or a 1200 W toaster in 10 minutes?
Advertisements
उत्तर
Energy consumed by the TV set,
E = p × t
= 250 × 1
= 250 Wh
Energy consumed by the toaster,
E = p × t
`= 1200 Wxx10/60h (10 min = 10/60h)`
= 200 Wh
Thus, it is clear that the TV set consumes more electrical energy.
APPEARS IN
संबंधित प्रश्न
The diagram below shows a circuit containing a lamp L, a voltmeter and an ammeter,. The voltmeter reading 3 V and the ammeter reading is 0.5 A.
What is the resistance of the lamp?
What is the power of the lamp?
How many joules are there in one kilowatt-hour?
An electric heater of resistance 8 Ω takes a current of 15 A from the mains supply line. Calculate the rate at which heat is developed in the heater.
State and define the household unit of electricity.
Distinguish between kilowatt and kilowatt-hour.
A current passes through a resistor. Let K1 and K2 represent the average kinetic energy of the conduction electrons and the metal ions, respectively.
What does the unit kilowatt hour measure? Define it.
What is ‘Rating’ of an electric appliance?
Why is the electric power from the generating station transmitted at high voltage?
An electric heater is rated 220 V, 550 W. Calculate the electrical energy consumed in 3 hours?
State the reason why, in a three pin plug, the earth pin is longer and thicker than the other two.
How can electric energy consumed by an electric appliance be calculated in kilowatt hour (kWh)?
A family uses a light bulb of 100W, a fan of 100W, and a heater of 1000W, each for 8 hours a day. If the cost of electricity is Rs. 2 per unit, what is the expenditure to the family per day, on electricity?
An electric lamp A of 40 W and another electric lamp B of 100 W are connected to 220 V supply. Calculate the ratio of their filament resistances?
A bulb is marked 100W, 220V and an electric heater is marked 2000 W, 220 V.
(i) What is the ratio between the resistances of these two devices?
(ii) How does the power-voltage rating of a device help us to decide about the type of leads (connecting wires) to be used for it?
(iii) In which of the above two devices, a thicker connecting wire of lead is required?
Unit of electric power may also be expressed as:
1 mV is equal to:
A electric bulb is rate 220 V, 60 W. its electric cell resistance is nearly
