Question

An alternating voltage is given by V = 20 sin 157 t. The frequency of the alternating voltage is _______​

Answer 1

SOLUTION

TO CHOOSE THE CORRECT OPTION

An alternating voltage is given by v = 20 sin 157t.

The frequency of the alternating voltage is

1) 75 hz

2) 100 hz

3) 25 hz

4) 50 hz

EVALUATION

Here it is given that an alternating voltage is given by

v = 20 sin 157t

Let f be the frequency of the alternating voltage

So by the given condition

Hence the frequency of the alternating voltage is 25 hz

FINAL ANSWER

Hence the correct option is 3) 25 hz

Answer 2

Answer:

If alternating current is represented by sinusoidal wave form, then we can write

i = im sin (ωt + ϕ)

Where i = current at time t

im = maximum current of the current waveform

ω = frequency in radian/sec

ϕ = phase shift

Calculation:

Given that,

i = 20 sin (157t) A

On comparing with standard equation,

im = 20 A

ω = 157 = 2× π × f

⇒ f = 25hz