[**NCERT In Text**]

An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 h.

Power (P) is given by the expression,P = VI

Where,

Voltage,V = 220 V

Current, I = 5 A

P= 220 x 5 = 1100 W

Energy consumed by the motor = Pt

Where,

Time, t = 2 h = 2 x 60 x 60 = 7200 s

∴ P = 1100 x 7200 = 7.92 x 10^{6} J

Therefore, power of the motor = 1100 W

Energy consumed by the motor = 7.92 x 10^{6} J

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R’, then the ratio R/R’ is -

(a) 1/25

(b) 1/5

(c) 5

(d) 25

Ans (d) 25

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

(a) I^{2}R

(b) IR^{2}

(c) VI

(d) V^{2}/R

Ans (b) IR^{2}