Question

Which of the following does not represent electrical power in a circuit?

(a) I2R

(b) IR2

(c) VI

(d) V2/R

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Answer 1

Answer:

• Option (B) IR²

Explanation:

Electrical power is given by the expression ;

↪P = VI __________eqn.(1)

According to Ohm’s law,

↪V = IR $\purple\bigstar$

Substituting the value of V in (1), we get

↪P = (IR) × I

↪P = I²R

Similarly, from Ohm’s law,

↪I = V/R

Substituting the value of I in (1), we get

↪P = V × V/R

↪P = V²/R $\red\bigstar$

From this, it is clear that the equation IR² does not represent electrical power in a circuit.

Answer 2

P = VI ....... (I)

Hence, option (c) represents power.

V = IR..........(ii)

From (I) and (ii)

P = I²R

P = V²/R

Hence, option (a) and (d) represents power too

Therefore, option (b) doesn't represent power.