# Electrical Power

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Power means rate of doing work. Whenever, voltage causes electron movement, work is done in moving electrons/ charge from one point to another. The rate at which work is done is called electric power. Its symbol is ‘P’. The basic unit of power is the Watt, which equals the voltage multiplied by the current. Its symbol is Watt. The wattmeter is used for measuring power.
To find the power, following formula is used -

P = E ´ I
Where,

P = Power, in watt,

E = Voltage, in volt,

I = Current, in ampere.
Ex. 1 An electric resistance iron takes a current of 4 ampere at a e.m.f. of 230 Volts, calculate the power of lamp?
Ans: P = E ´ I

= 230 ´ 4

= 920 Watts
Horsepower–It is a unit of measurement of mechanical power.Its symbol is hp

1hp = 75mkg / s

= 75 ´ 9.81

= 735.5 Nmls or watt. (1 kg weight = 9.81N).

1. Define the electrical power?

2. An electric heater takes a current 4.35 ampere at EMF of 230 volts calculate the power of electric heater?

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