Question

Please help me in deriving the equation P = VI

Answer 1

P = Work / time = W / t
Now,
Potential difference = Work done / charge moved
V = W / Q
W = V*Q

Substituting this in P= W / t

P = W/t
P = V*Q/t. .......2

Now,
Current I = Charge Q / time t
I = Q/t

Now substituting this for Q / t in equation 2

P = V * Q / t
P = V * I

Hence derived.