Advertisements
Advertisements
प्रश्न
Advertisements
उत्तर
APPEARS IN
संबंधित प्रश्न
Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?
Which quantity has the unit of watt?
The SI unit of energy is :
(a) joule
(b) coulomb
(c) watt
(d) ohm-metre
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?
An electric toaster draws 8 A current in a 220 V circuit. It is used for 2 h. Find the cost of
operating the toaster if the cost of electrical energy is Rs. 4.50 per kWh.
Express watt hour and kilowatt hour in joule.
What changes in energy occur in an electric heater?
State other bigger units of electric power and express them in watt.
How can electric energy consumed by an electric appliance be calculated in kilowatt hour (kWh)?
An electrical appliance is rated 1500 W, 250 V. This appliance is connected to 250 V mains. Calculate:
(i) the current drawn,
(ii) the electrical energy consumed in 60 hours,
(iii) the cost of electrical energy consumed at Rs. 2.50 per kWh.
