Question

(a) Write an expression for the heat produced in a conductor connected to a source of
potential difference 'V' when a current 'I' flows through it for some time 't'.​

Answer 1

Answer:

heat h = VI÷t for all substance

Answer 2

Answer:

When an electric charge Q moves against a p.d. V, the amount of work done is given by

W=Q×V ---------------(1)

We know, current , I=

t

Q

Q=I×t ------------(2)

By ohm's law ,

I

V

=R

V=I×R --------------(3)

Putting eqs. (2) and (3) in eq. (1),

W=I×t×I×R

W=I

2

Rt

Assuming that all the electrical work done is converted into heat energy , we get

Heat produced , H=I

2

Rtjoules

This relation is known as Joule's law of heating.