Question

P = Power, V = Voltage, I = Current, and R = Resistance. Which of the following relations is incorrect?

Choices:

V = I R

P = V R

P = VI

I = V/R

Answer 1

The incorrect relation is P = V R

Explanation :-

* According to ohm's law, at a certain temperature the potential difference (V) across a conductor is directly proportional to current (I) carried by the conductor.

V I

V = I*R

Where R is the resistance across the conductor.

Also we can write the expression for current,

Electrical power is defined as the rate of electric work done by the circuit per time. According to Joules law,  the heat energy ( electrical work) produced in a conductor is equal to the product of square of current passing the it, resistance across the conductor and time which take to pass the current.

This heat energy is same as the work done. Therefore power,

Where

Conclusion :-

Following relations are correct.

* V = I*R

* P = V * I

* I = V/R

But P = V * R ​​​​​​​is incorrect relation