2026 Alternating CurrentInstantaneous value of alternating current Medium Question 2 of 60 in Alternating Current

The peak value of an alternating current is 5 A and frequency is 60 Hz. How long will the current, starting from zero, take to reach the peak value?

A $\frac{1}{240}$ s
B $\frac{1}{30}$ s
C $\frac{1}{120}$ s
D $\frac{1}{60}$ s

The answer is A.

Solution

$I = I_0 \sin\omega t$ $I = I_0$ when $\omega t = \frac{\pi}{2}$ $\Rightarrow (2\pi f)t = \frac{\pi}{2} \Rightarrow 2\pi \times 60 \times t = \frac{\pi}{2}$ $\Rightarrow t = \frac{1}{240}$ s

Alternating Current in past papers

60 questions from this chapter have appeared across 24 exam years.