Advertisements
Advertisements
Question
State other bigger units of electric power and express them in watt.
Solution
The other bigger units of power commonly used are:
1 kilowatt = 1000 watt
1 Horse power (H.P.) = 746 watt
Megawatt = 106 watt
APPEARS IN
RELATED QUESTIONS
Name the quantity whose unit is (i) kilowatt, and (ii) kilowatt-hour.
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.
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?
Name the physical quality which is measured in
(i) Kw (ii) kWh
An electric bulb is rated 250 W, 230 V. Calculate:
- the energy consumed in one hour
- the time in which the bulb will consume 1.0 kWh energy when connected to 230 V mains.
What is the current I in the given circuit (Fig. )?
At what voltage is the electric power generated at the generating station? Explain the transmission of this power to your house.
The equation I2R seems to suggest that the rate of heating in a resistor is reduced if resistance decreases, whereas equation P = V2/R suggests just the opposite. How do you reconcile this problem?
