Define electric power. An electrical device of resistance R isected ac

1.	Define electric power. An electrical device of resistance R isected across a source of voltage V and draws a current IDerive an expression for power in terms of current and resistance.
Answer» a) Electric power is the electricalwork doneper unit time .That is , Power = Workdone / Time taken = W/t The S.I. unit of electric power is watt which is denoted by the letter W.Thepower of 1 watt is a rate of working of 1 joule per second.That is, 1 watt = 1 joule/1 second (b)Expression for Power in terms of V and I We know that : Power = Work done/Time taken or P = W/t the work done W by current I when it flows for time t under a potential difference V is given by : W = V x I x t joules Putting this value of W in equation P = W/t,we get : P = V I t / t joules per second or Power,P = V x I watts where V = Potential difference (or Voltage) in volts and I = Current in amperes Thus,the power in watts is found by multiplying the potential difference in volts by the current in amperes. Like if you find it useful

Define electric power. An electrical device of resistance R isected across a source of voltage V and draws a current IDerive an expression for power in terms of current and resistance.

Answer»

a) Electric power is the electricalwork doneper unit time .That is ,

Power = Workdone / Time taken

= W/t

The S.I. unit of electric power is watt which is denoted by the letter W.Thepower of 1 watt is a rate of working of 1 joule per second.That is,

1 watt = 1 joule/1 second

(b)Expression for Power in terms of V and I

We know that :

Power = Work done/Time taken

or P = W/t

the work done W by current I when it flows for time t under a potential difference V is given by :

W = V x I x t joules

Putting this value of W in equation P = W/t,we get :

P = V I t / t joules per second

or Power,P = V x I watts

where V = Potential difference (or Voltage) in volts

and I = Current in amperes

Thus,the power in watts is found by multiplying the potential difference in volts by the current in amperes.

Like if you find it useful