Here are some questions to complete after you have determined the wavelength with a diffraction grating. (A laser was used)
equation used: n x lambda=d x sintheta
Question:
What effect will the following have on the pattern produced? Explain your reasoning:
1.increasing distance to screen, D
2.changing from red light to green light
3.rotating the diffraction grating through ninety degrees
4.using a point source of white light
2nd Attempt:(sorry the resource didnt help with this specifically so i just thought more)
1.Increasing the distance to the screen would mean would mean a bigger x1 which would mean a bigger angle and a bigger slit spacing. It would also mean a smaller wavelength.
2.Red light has a bigger wavelength than green light. Red light had 700nm while green light has around 500nm. As i know this fact i know that at the end of the experiment the wavelength i would find would be smaller than before if i used green light.
3.Rotating the diffraction grating would mean the wavelength also rotate and are no longer horizontal so wouldnt go through the slit.
4.White light is all sorts of wavelengths so it would cause the slit spacing and wavelength to increase.
I have gone through the text book, my work, websites, nothing gives information specific to these questions or anything that applies to them so im hoping someone can help ,me .I like this website for the teacher help. Maybe tell me if this is right and what else to say and if by pattern i just say increase/decrease.
Please help, ive been waiting over 4 hours for this question help and the library is about to close.
1. Why would wavelength change, it has nothing to do with distance from screen.
2. I think it is asking what happens to angles on Red vs Green. see what the angle (or the tan/sin of the angle does as wavelenth cnages)
3. with a point source, the pattern would be vertical, but without a point source, like a laser, you are right.
4. wavelength do not depend on the slit, or spacing, or distance. It is from the light. With many colors, you get overlapping patterns of individual patterns.
1. Increasing distance to the screen (D):
Increasing the distance to the screen will have a couple of effects on the pattern produced. Firstly, it will cause the distance between adjacent bright spots (fringes) to increase, resulting in a wider pattern. This is because the fringe spacing, represented by d in the equation nλ = d sinθ, is directly proportional to the distance to the screen (D). Secondly, increasing the distance to the screen will decrease the angle (θ) at which the fringes are observed. This is because, for a fixed wavelength, as the distance to the screen increases, the angle at which the fringes are observed decreases, as given by the equation. So, increasing the distance to the screen will result in a wider pattern with fringes observed at smaller angles.
2. Changing from red light to green light:
Changing from red light to green light will have an effect on the wavelength (λ) used in the equation. Green light has a smaller wavelength than red light. So, if you change from red light (with a longer wavelength) to green light (with a shorter wavelength), the value of λ in the equation will be smaller. This means that the distance between adjacent bright spots (fringes) will decrease, resulting in a tighter pattern.
3. Rotating the diffraction grating through ninety degrees:
Rotating the diffraction grating through ninety degrees will have a significant effect on the pattern produced. The pattern will no longer be observed as a set of bright fringes because the diffraction grating will no longer be properly aligned. Instead, the pattern will be distorted or completely disappear depending on the alignment of the grating. Therefore, rotating the diffraction grating will prevent the formation of a clear pattern.
4. Using a point source of white light:
Using a point source of white light will result in a different pattern compared to using a laser with a single wavelength. White light consists of a range of wavelengths, so each wavelength will produce its own pattern according to the equation. This means that instead of observing a series of fringes with a single wavelength, the pattern will be a combination of multiple overlapping patterns produced by different wavelengths. The resulting pattern will appear as a blend of colors rather than distinct fringes.