Question

In an a.c. circuit V and I are given by

V = 100 sin (100 t) volts

I = 100 sin (100 t + p/3) mA

the power dissipated in the circuit is-

• A. 10⁴ watt
• B. 10 watt
• C. 2.5 watt
• D. 5.0 watt

Answer 1

Answer: (C)

2.5 watt

Answer 2

P = V_rms I_rms cos f

= $\left( \frac { 100 } { \sqrt { 2 } } \right)$ $\left( \frac { 100 } { \sqrt { 2 } } \right)$ × 10^–3 cos $\frac { \pi } { 3 }$

= 2.5 W