Question

State and explain the joules law​

Answer 1

Answer:

Joule’s law of heating states that when a current ‘i ' passes through a conductor of resistance ‘r’ for time ‘t’ then the heat developed in the conductor is equal to the product of the square of the current, the resistance and time.

H = i 2 rt

The reason behind the heat produced is the collision of the free electrons with the lattice ions or atoms while accelerating in presence of the external electric field.

we know that

volt= work done/ total charge or v = w/q

from this we get w= vq

we know that current i = q / t

so q = it

putting this in prev equation

we get w = vit

from ohms law v = ir

putting it in prev eq we get

w = irit = i2rt joule as work is stored as heat soH = I2RT Joules

if a current carrying conductor having resistance (r) gets heated by to passing of current (i) for time (t) and the heat thereby produced be H

joules law states that

H propotional to i^ 2 when r and t are constant

H propotional to r when I and t are constant

H propotional to t when r and I constant