Advertisements
Advertisements
प्रश्न
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?
Advertisements
उत्तर
The energy consumed in a resistor when the potential difference is 1V and 1A current flows for 1000 hrs.
संबंधित प्रश्न
An electric bulb is connected to a 220 V power supply line. If the bulb draws a current of 0.5 A, calculate the power of the bulb.
An electric bulb is rated at 220 V, 100 W. (a) what is its resistance? (b) what safe current can be passed through it?
The coil of an electric bulb takes 40 watts to start glowing. If more than 40 W are supplied, 60% of the extra power is converted into light and the remaining into heat. The bulb consumes 100 W at 220 V. Find the percentage drop in the light intensity at a point if the supply voltage changes from 220 V to 200 V.
Point out two main disadvantages of ‘Tree System’.
The electric bulbs used these days have a coil-coiled filament. State its reason.
An electric heater is rated 220 V, 550 W. Calculate the electrical energy consumed in 3 hours?
An electric iron is rated at 230 V, 750 W. What is its resistance? What maximum current can be passed through it?
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?
Two heaters A and B have power rating of 1 kW and 2 kW, respectively. Those two are first connected in series and then in parallel to a fixed power source. The ratio of power outputs for these two cases is ______
