Question

What is Joule’s heating effect of current P ? Derive its expression.

Answer 1

hey mate !!!

Jule's law :-

according to this law.

the heat produced by register is :-

1) directly proportional to a square of current flowing through the resistance.

$h \: directly \: propotional \: to \: i {}^{2}$
-----------(1).

2) directly proportional to resistance for given current

=>>H is directly proportional to R -----(2)

3) directly proportional to the time , for which current is flowing .

H is directly proportional to t --------(3)

from first second and third equation we get.

$h = i {}^{2} rt$

from ohm' s law we have also H = IVT

hope it helps!!!

thanks

Answer 2

According to Joules law of heating, when a current I flows through a resistance R then :
Heat produed is directly proprtional to 
1. Square of current (I²)
2)Resistance of wire R.
3) time (t) for which current is passed.
H=I²Rt

Derivation:

let us consider a resistance R , in which I amount of current flows.
Work must be done by current to move continuously.
W=Qx V
BUT Q=IXt
W=IxVxt
but from ohms law: V=IR
W=I²Rt
assuming the electrical energy consumed is converted into heat energy .
we write workdone as Heat  produced
so 
H=I²Rt
hence derived