Physics Interference & Diffraction
posted by Christina
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?
*Answer: 7 (this is correct)
Part B: What is the angle of the bright spot farthest from the center?
*Answer: ???
I am not sure what equation to use for this part of the problem....

drwls
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. 
Christina
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?
*Answer: ?????
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
Respond to this Question
Similar Questions

physics
A diffraction grating gives a secondorder 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? 
physics
A diffraction grating gives a secondorder 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? 
physics
A double slit diffraction pattern is formed on a distant screen using mercury green light of wavelength 546.1 nm. Each slit has a width of 0.1 mm. The pattern shows that the 4th order interference maximum is missing. a) What is the … 
physics
Monochromatic light of wavelength 550 nm passes through a diffraction grating that has 55000 lines/m. A bright line appears on the screen at an angle of 12.23o from the central bright fringe. What is the order of this bright line? 
Physics
The light shining on a diffraction grating has a wavelength of 470 nm (in vacuum). The grating produces a secondorder bright fringe whose position is defined by an angle of 9.35°. How many lines per centimeter does the grating have? 
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 of … 
Physics
Monochromatic light of wavelength 550 nm passes through a diffraction grating that has 55000 lines/m. A bright line appears on the screen at an angle of 12.23o from the central bright fringe. What is the order of this bright line? 
Physics, diffraction
1. Yellow light of wavelength 580 nm shines on a diffraction grating with 4000 lines/cm. A.At what angles do the firstorder and secondorder maxima occur? 
Physics, diffraction, interference, help!
3.Blue light (λ = 450 nm) shines on a diffraction grating that has 4000 lines/inch. A.Calculate the angle of the fourthorder image 
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. A) …