Question

Name and define the smallest commercial unit of electric energy.

Answer 1

Definition of electric energy:

“The product of power and time i.e. electric energy consumed by an electric appliance or any other device in the given amount of time is termed as electric energy.”

Smallest commercial unit of electric energy:

“Joule” is the smallest commercial unit of electric work

Definition of smallest commercial unit of electric energy:

$E=P\times t$ ($1$) ,

Here $P$ is power, $E$ is electric energy and $t$ is time.

We know that $P=VI$ (the expression of power in terms of potential difference and current)

Substitute $P=VI$ in equation($1$),

$E=P\times t$

$E=VIt$

From the above expression we can say that, $1$ Joule is the amount of work executed when a cost of one coulomb flows through a conductor at a potential difference of $1$ volt.

$1joule=1volt\times 1coulomb$