I wanted to ask if the sine wave can only have 1 frequency which is

standard or it can take the form of more than 1 frequency.

The simple answer is that in popular usage a sine wave is only a single

frequency.

But in the real world there is always noise riding on that sine wave, and

possibly other sine waves of smaller amplitude. So if you look at your

sine wave on a spectrum analyzer, you will find that the peak is not a

spike, such as you would see in a purely mathematical Fourier transform,

but is spread out over some frequency range.

You would also see that there are harmonics present. That is to say, there

are components at 2x, or 3x or some higher integer multiple of the

fundamental sine wave frequency.

What made you think to ask this question here instead of, say,

sci.electronics.basic?

--Mac