Question

The instantaneous value of current in an a.c. circuit is I = `2 sin [100 pi t + pi/3]` A. The curent wil be maximum for the first time at ______.

(sin 90° = 1)

Options

• `1/100 s`

• `1/200 s`

• `1/400 s`

• `1/600 s`

Answer 1

The instantaneous value of current in an a.c. circuit is I = `2 sin [100 pi t + pi/3]` A. The curent wil be maximum for the first time at `bbunderline(1/600 s)`.

Explanation:

Given: I = `2 sin [100 pi t + pi/3]` A

Peak value (I₀) = 2A

When I = 2 A, we have

2 = `2 sin [100 pi t + pi/3]`

∴ `sin [100 pi t + pi/3]` = 1

∴ `100 pi t + pi/3 = pi/2`

∴ 100 πt = `pi/6`

⇒ t = `1/600` s