Physics diffraction gratings

Watch
16gbirch
Badges: 1
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
Report Thread starter 1 month ago
#1
How many principal maxima are produced when a grating with spacing of 2.00 x 10^-6 m is illuminated normally with light of wavelength 6.44 x 10^-7 m?
0
reply
Mr Wednesday
Badges: 19
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report 1 month ago
#2
Calculate the angle between different maxima, then consider what the largest possible "real" angle can be as a function of diffraction order.
0
reply
BlueBazooka
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
Report 1 month ago
#3
By rearranging the diffraction grating equation we receive the result n = (d*sin(theta))/wavelength
The maximum value for theta at which maxima can be produced is 90 degrees, as you can't have maxima be behind you, only to the right and left.
Plugging that into the above, we have n = d/wavelength where n is the maximum order observed. Calculate n and round it down to the integer below it, as you cant have a fraction of a maximum (so n must be a whole number).
The number of orders observed then is simply 2n + 1 (you have n orders each side of the centre so it must be multiplied by 2, and then you must add on the central 0th order maximum).
Last edited by BlueBazooka; 1 month ago
2
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

When did you submit your Ucas application if you applied to go to university this year?

September 2021 (30)
7.09%
October 2021 (194)
45.86%
November 2021 (44)
10.4%
December 2021 (56)
13.24%
January 2021 (46)
10.87%
I still haven't submitted it yet! (39)
9.22%
Something else (14)
3.31%

Watched Threads

View All
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise