Advertisements
Advertisements
प्रश्न
Which one has a higher electrical resistance : a 100 watt bulb or a 60 watt bulb?
Advertisements
उत्तर
A 60-watt bulb has a higher electrical resistance than a 100-watt bulb. Because power is inversely proportional to resistance, when the power is less, the resistance is high.
APPEARS IN
संबंधित प्रश्न
Define Electric power.
Two lamps, one rated 100 W at 220 V, and the other 60 W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V?
What is consumed using different electrical appliances, for which electricity bills are paid?
An electric bulb is rated at 220 V, 100 W. What is its resistance?
What is the meaning of the symbol kWh? Which quantity does it represent?
An electric lamp is labelled 12 V, 36 W. This indicates that it should be used with a 1 V supply. What other information does the label provide?
Define kilowatt-hour.
The table below shows the current in three different electrical appliances when connected to the 240 V mains supply:
| Appliance | Current |
| Kettle | 8.5 A |
| Lamp | 0.4 A |
| toaster | 4.8 A |
- Which appliance has the greatest electrical resistance? How does the data show this?
- The lamp is connected to the main supply by using a thin, twin-cored cable consisting of live and natural wires. State two reasons why this cable should not be used for connecting the kettle to the mains supply.
- Calculate the power rating of the kettle when it is operated from the 240 V mains supply.
- A main takes the kettle abroad where the mains supply is 120 V. What is the current is the kettle when it is operated from the 120 V supply?
What changes in energy occur in an electric heater?
‘The current rating of a fuse is 5A’. Comment on this statement.
How does the heat produced by die passage of current in a metallic wire depend on the resistance of the wire.
How does the heat produced by die passage of current in a metallic wire depend on the time of passage of current in the wire?
An electric bulb is rated 240V-60W and is working at 100% efficiency.
(i) Calculate the resistance of bulb.
(ii) (a) Draw the circuit diagram.
(b) What is the rate of conversion of energy in each bulb?
(c) Total power used by the bulbs.
State (i) the S. I. unit, (ii) the household unit, of electrical energy. How are these units related?
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?
An electric iron is rated at 230 V, 750 W. What is its resistance? What maximum current can be passed through it?
A cooler of 1500 W, 200 volts and a fan of 500 W, 200 volts are to be used from a household supply. The rating of fuse to be used is:
