Advertisements
Advertisements
प्रश्न
How can electric energy consumed by an electric appliance be calculated in kilowatt hour (kWh)?
Advertisements
उत्तर
The electric energy in kWh van be calculated as follows:
Energy in kWh = `("Power" ("in watt") xx "Time"("in hour"))/1000`
or kWh = `("V"("volt") xx "i" ("ampere") xx "t" ("hour"))/1000`
∴ Energy (in kWh) = `"Vit"/1000`
संबंधित प्रश्न
Calculate the cost of operating a heater of 500 W for 20 hours at the rate of Rs 3.90 per unit.
When an electric lamp is connected to 12 V battery, it draws a current of 0.5 A. The power of the lamp is:
(a) 0.5 W
(b) 6 W
(c) 12 W
(d) 24 W
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)?
A potential difference of 6 V is applied across a 3 Ω resistor. What is the current flowinq throuqh the circuit?
Two resistors A and B of 4 Ω and 6 Ω, respectively are connected in parallel. The combination is connected across a 6 volt battery of negligible resistance. Calculate the power dissipated in each resistor.
Which cable, one rated 15A and the other rated 5A will be thicker? Give a reason.
State the reason why, in a three-pin plug, the earth pin is longer and thicker than the other two.
Find the heat produced in joules when a current of 10 amperes flows through a connecting wire of resistance 2 × 10-2 ohms and heating element of resistance 250 ohms for 2 seconds.
Find the energy released by a current of 0.25 amperes flowing through a heater for 5 minutes. The p.d. is 230 V.
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?
