Getting monochromatic light from white light/sunlight & young double slit?

Question

I am assuming that sunlight is white light anyway...
I'd like to measure the wavelengths of different coloured light in a lamp that emits light similar to that of 'natural sunlight' using Youngs Double Slit Exp

To get monochromatic light, that is of the ROYGBIV colours, would I just place a coloured filter in front of the white light source? [and proceed to carry on with the exp as its usually done...]

Also, is there a formula or relationship between the intensity of the light and wavelength?

And lastly (sorry for the longness), can anyone see how it is possible to incorporate a LDR with the experiment?

Thank you sooooo much!!

Answer 1

The energy of each photon of light is a basic property. It turns out that there is a simple relationship between the energy of a photon and the corresponding wavelength of that photon:

E(photon) = (constant) / (wavelength).

This simple equation basically ties together the particle and wave nature of light by permitting us to convert back and forth from wavelengths to photons and photons to their corresponding wavelengths. An X-ray photon has a large energy (and a small wavelength) compared with a photon of optical light.

Take a look at the following website for some answers to the portion of your question dealing with Young's Double Slit experiment:

http://galileoandeinstein.physics.virginia.edu/more_stuff/flashlets/youngexpt4.htm

You may need to cut and paste!

Dr. H

Answer 2

Young's double slit experiment demonstrates the concept of diffraction. The image seen after the double slit has multiple peaks with separation that is proportional to the wavelength of the light. If you have a continuous light source like the sun (or a sun-like lamp), these peaks might blur together making it hard to distinguish. You will see repeating rainbow like patterns. If you can use a prism instead, you will get a similar result but it might be easier to see. Try putting different colored filters in front of the light source and see how the pattern changes. Usually, unless you are using special optical grade filters, the spectrum is still broad and not what you would really call monochromatic.

The spectrum (formula for intensity vs. wavelength) of the sun is that of a blackbody with some adjustments for the effects of absorption in the Earth's atmosphere. Wikipedia has some nice graphs (http://en.wikipedia.org/wiki/Solar_radiation).

I am not sure what your ultimate goal is (a school project perhaps?), but a photoresistor could be used as a sensor to detect changes in color or help you measure the amount of light by position and thus act like a spectrometer.

Answer 3

The intensity of light has nothing to do with wave length or color. If u are getting color changes . something in your test setup is wrong .

Answer 4

frequency decreases
wavelenght increases

and vice versa