# Physics -Interference & Diffraction

Given Information: Light of wavelength 631 nm passes through a diffraction grating having 485 lines/mm.

Part A: What is the total number of bright spots (indicating complete constructive interference) that will occur on a large distant screen?

Part B: What is the angle of the bright spot farthest from the center?
-I am not sure what equation to use for this part of the problem....

1. 👍 0
2. 👎 0
3. 👁 230
1. There will be a bright spot wherever
d sin A = N *lambda,
where lambda is the wavelength, d is the line spacing, and N is an integer (including zero).

(1/485)*10^-3 m sin A = N*631*10^-9 m
sin A = N* 0.306

Allowed values of N are +/-1,2,3 and 0
So there are seven bright spots

B. The center of the pattern is n=0. Compute the angle for which N = + or - 3 and you will have the answer.

1. 👍 0
2. 👎 0
posted by drwls
2. Ooh wonderful! There is another problem similar to it...I am having trouble finding the # of fringes, but I think once I get help with that I can solve for the angle!!!

GIVEN: Light of wavelength 585 nm falls on a slit 6.66×10−2 mm wide.

Part A: On a very large distant screen, how many totally dark fringes (indicating complete cancellation) will there be, including both sides of the central bright spot?

Part B: At what angle will the dark fringe that is most distant from the central bright fringe occur?
*Answer: I'm asuming that this will be the equation to use: d*sinA=(N+.5)*L

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Physics

Diffraction grating #1 has half the lines/cm that diffraction grating #2 does. When used with a certain wavelength of light, both gratings give first order maxima. Which of the following statements is true for the same wavelength

asked by Lexi on July 27, 2012
2. ### Physics

Diffraction grating A has 16 000 lines/cm, and diffraction grating B has 12 000 lines/cm. Light of the same wavelength is sent through both gratings to a screen located a distance L from the gratings. The spacing of the maxima for

asked by Anonymous on January 18, 2018
3. ### PHYSICS

1) A diffraction grating with 2.500 x 10^3 lines/cm is used to examine the sodium spectrum. Calculate the angular separation of the two closely spaced yellow lines of sodium (588.995 and 589.592) in each of the first three orders.

asked by Anonymous on October 22, 2008
4. ### physics

A diffraction grating gives a second-order maximum at as angle of 31‹ for violet light (ƒÉ = 4.0 ~ 102 nm). If the diffraction grating is 1.0 cm in width, how many lines are on this diffraction grating?

asked by Rach on January 6, 2010
5. ### physics

A diffraction grating gives a second-order maximum at as angle of 31‹ for violet light (ƒÉ = 4.0 ~ 102 nm). If the diffraction grating is 1.0 cm in width, how many lines are on this diffraction grating?

asked by Rach on January 6, 2010
6. ### Physics

The light shining on a diffraction grating has a wavelength of 470 nm (in vacuum). The grating produces a second-order bright fringe whose position is defined by an angle of 9.35°. How many lines per centimeter does the grating

asked by DCM on March 13, 2012
7. ### Physics

Light of wavelength 600 nm illuminates a diffraction grating. The second-order maximum is at angle 39.1°. How many lines per millimeter does this grating have?

asked by Roby on March 31, 2011
8. ### As physics

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

asked by 0oooooooo0 on March 15, 2018
9. ### Physics

Laser light of wavelength 550 nm falls upon a diffraction grating. The slits are 25 micrometers apart and each have a width of 2 micrometers. There is a screen 2 meters away from the diffraction grating, parallel to the grating.

asked by Lexa on May 3, 2016
10. ### physics

Why is white light separated into a spectrum of colors when it is passed through a diffraction grating? The diffraction angle (theta) is given by n x (lambda) = d sine(theta) where lambda = wavelength theta = diffraction angle d =

asked by anonymous on April 27, 2007

More Similar Questions