about light

[darko]

as i know light has a range of frequency.

..??? :
1.but i ever read an article, told that sunlight is zero frequency(DC) is that right,how come?

2.are there any differences between any source of light in their frequency, what are they?

3.if i make a circuit to detect a source of light and have to eliminate the noise from sunlight can i make a filter(low pass or high pass filter)?

4.is the light with certain frequency will make electric signal with the same frequency in a circuit of photodetector?

thanx before...........

[audioguru]

as i know light has a range of frequency.

Yes, the frequencies of all the colors.

1.but i ever read an article, told that sunlight is zero frequency(DC) is that right,how come?

No. Sunlight is white. White light contains many colors. Many colors are at many frequencies.

2.are there any differences between any source of light in their frequency, what are they?

A color chart shows the wavelengths of different colors. The wavelengths are related to the extremely high frequencies.

3.if i make a circuit to detect a source of light and have to eliminate the noise from sunlight can i make a filter(low pass or high pass filter)?

Sunlight has many frequencies so a filter won't make any difference. You will need to filter (block) all light including the source of light that you want to detect.

4.is the light with certain frequency will make electric signal with the same frequency in a circuit of photodetector?

A photodetector makes a DC output when it detects any color of light that it is sensitive to. Add a color filter in front of it for it to have an output for that color.

The frequency of each color of light is far higher than electronic circuits can make or detect.
The highest radio frequency today is 300GHz. Light frequencies are 1000 and more times higher.