Question

prove joules law of heating​

Answer 1

Explanation:

Solution :

(a) Joule's law of heating . When a current (I) flows through a resistor of resistance for time (t), then the amount of heat produced (H) is given by

H=I2×R×t

This is known as Joule's law of heating.

The heat produced in the wire is directly proportional to :

square of current (I2)

resistance of wire (R )

time (t) for which current is passed.

Given : Lamp (1) = 100W , 220 V

Lamp (2) =60W,220V

I1=?,,I2=?

V1=V2=V=220V

P1=V1×I1

100=200×I1

I1=100220=511=0.45A

P2=V2×I2

60=220×I2

I2=60220=0.27A

Answer 2

Answer:

Explanation:

The workdone by a current I when it flow through a resistance R for time t . now, when an electric charge Q moves againts a potential difference V the amount of work done is given by

W = Q*V ........... eq1

we know that I =Q/T , Q = I*T

Accordind to ohms law  V= I*R

Now putting Q =I*T AND V= I*R in equation 1

W = I*t*I*R

so work done = I^2*R*T

Assuming that aal the electirc work done or all the electric energy consumed is converted into heat energy, we can write "Heat produced' in place of work done in above equation

heat produced , H= I^2*R*T