- #1

lorenz0

- 148

- 28

- Homework Statement
- A diffraction grating with ##N## lines per unit length is used initially with monochromatic light of wavelength ##\lambda##.

How many bright fringes are seen in total:

(1) On a screen of width ##W## distant ##L## from the grating;

(2) On a screen of infinite width?

(3) The monochromatic light is replaced with white light:

say what appears now on the screen of infinite width, indicating the difference(s) with respect to the previous setup with monochromatic light.

- Relevant Equations
- ##\Delta y=\frac{\lambda}{d}##

(1) In the book I am using the separation of bright fringes is indicated as being ##\Delta y=\frac{\lambda}{d}##, where ##d## is the separation of the slits so on a screen of width ##W## I would see ##\frac{W}{\frac{\lambda}{\frac{1}{N}}}## bright fringes. I don't see why the text of the exercise mentions the distance from the grating since it doesn't appear in the formula for the distance between bright fringes.

(2) Although the intensity of the maxima gradually diminishes with the distance from the center, it doesn't become ##0## so, in theory, there should be an infinite number of maxima on an infinite screen.

(3) If white light is used the diffraction maxima are separated into different wavelength components.

I am still trying to wrap my head around the concept of diffraction so I would appreciate if someone would give me some feedback on my solution (and on how to better understand diffraction) thanks.

(2) Although the intensity of the maxima gradually diminishes with the distance from the center, it doesn't become ##0## so, in theory, there should be an infinite number of maxima on an infinite screen.

(3) If white light is used the diffraction maxima are separated into different wavelength components.

I am still trying to wrap my head around the concept of diffraction so I would appreciate if someone would give me some feedback on my solution (and on how to better understand diffraction) thanks.