Posted by physics on Saturday, March 14, 2009 at 12:56pm.
Monochromatic light from a heliumneon laser (wavelength=632.8 nm) shines at a right angle onto the surface of a diffraction grating that contains 130 960 lines/m. Find the angle at which one would observe the firstorder maximum.
formula: (a+b)Sin theta = n wavelength
(a+b) = 1
____ m; n=1
wavelength=632.8*10^9 m
=6.328*10^7m
Sin theta=6.32^8 * 10^7 * 130960
= 6.328*10^7*130960*10^5
theta= 4.7536deg
= 4.75
is this done correctly?
130960

physics  drwls, Saturday, March 14, 2009 at 1:15pm
I don't know what a and b are supposed to be in your diffrection grating formula. The correct form of the quation is
d (sin i + sinr) = m*lambda
where i and r are the angles of incidence and reflection.
In your case sin i = 0, m = 1, and d is the grating line separation, which is your case is 1/(130960m^1) = 7.636*10^6 m.
Therefore
d sin r = 632.8*10^9 m
sin r = 632.8*10^9*130960 = 0.08287
r = 4.75 degrees
So you got the right answer, anyway
Answer This Question
Related Questions
 physics  pleaase help me with this, i'm very bad in physics, and i mostly don't...
 PHYSICS  1) A diffraction grating with 2.500 x 10^3 lines/cm is used to examine...
 physics  Why is white light separated into a spectrum of colors when it is ...
 Physics  I'm working on a final physics exam, and I've got everything but these...
 physics  A diffraction grating gives a secondorder maximum at as angle of 31...
 physics  A diffraction grating gives a secondorder maximum at as angle of 31...
 Physics  When light of a certain wavelength is incident normally on a certain ...
 Physics, diffraction  1. Yellow light of wavelength 580 nm shines on a ...
 Physics  Light of wavelength 600 nm illuminates a diffraction grating. The ...
 physics  1) If the first order maximum of HeNe light exits a diffraction ...
More Related Questions