Question

The r.m.s. value of alternating current is 10 A, having frequency of 50 Hz. The time taken by the current to increase from zero to maximum and the maximum value of current will be ______. 

Options

• 2 × 10^-2 sec and 14.14 A 

• 1 × 10^-2 sec and 7.07 A 

• 5 × 10^-3 sec and 7.07 A 

• 5 × 10^-3 sec and 14.14 A

Answer 1

The r.m.s. value of alternating current is 10 A, having frequency of 50 Hz. The time taken by the current to increase from zero to maximum and the maximum value of current will be 5 × 10^-3 sec and 14.14 A. 

Explanation:

Time taken to reach the current from 0 to maximum = `"T"/4`

Time period (T) = `1/"f"=1/50`

= `1/200`

= 5 × 10^–3 s

I_rms = 10 A

I_rms = `"I"_0/sqrt2`

I₀ = I_rms × `sqrt2`

= 10`sqrt2` A

= 14.14A