Question

Find the time in which a 100 Hz alternating current changes from zero to its rms
value​

Answer 1

Explanation:

Alternating current i=i

o

sinwt

where w=2πf=2π×50=100 π

For i=i

rms

=

2

i

o

We get

2

i

o

=i

o

sinwt

Or sinwt=

2

1

Or wt=

4

π

Or 100π×t=

4

π

We get t=

400

1

seconds

Answer 2

Answer:

$\frac{1}{800}$

Explanation:

Alternating current i = $i_{0} sin wt$ --- (1)

Since, f = 100Hz

$w = 2\pi f = 2\pi (100) = 200\pi$ ---(2)

$i = i_{rms} = \frac{i_{0} }{\sqrt{2} } }$ --- (3)

From (1) and (3),

$i_{0} sin wt = \frac{i_{0} }{\sqrt{2} }$

$sin wt = \frac{1}{\sqrt{2} }$

$wt = \frac{\pi }{4}$

From (2),

$200\pi t = \frac{\pi }{4}$

$t = \frac{1}{800}$