Advertisements
Advertisements
Question
Define watt. Write down an equation linking watts, volts and amperes.
Solution
Watt is the unit of power. One watt can be defined as the power consumed by an electrical device if it is operated at a potential difference of 1 V and it carries a current of 1 A. That is:
1 watt = 1 volt x 1 ampere
APPEARS IN
RELATED QUESTIONS
Which one has a higher electrical resistance : a 100 watt bulb or a 60 watt bulb?
An electric fan runs from the 230 V mains. The current flowing through it is 0.4 A. At what rate is electrical energy transferred by the fan?
Which of the following is likely to be the correct wattage for an electric iron used in our homes?
(a) 60 W
(b) 250 W
(c) 850 W
(d) 2000 W
State and define the household unit of electricity.
What is the resistance, under normal working conditions of a 240 V electric lamp rated at 60 W? If two such lamps are connected in series across a 240 V mains supply, explain why each one appears less bright.
Name the physical quantity which is measured in kW.
What is electric power? State and define its S.I. unit.
‘The current rating of a fuse is 5A’. Comment on this statement.
A bulb is connected to a battery of e.m.f. 6V and internal resistance 2Ω A steady current of 0.5A flows through the bulb. Calculate the resistance of the bulb.