- #1
chef99
- 75
- 4
Homework Statement
Light from a laser with a wavelength of 760nm is directed at diffraction grating of 1500 lines/cm. If the diffraction grating is located 15.m from the screen, calculate the distance between adjacent bring fringes.
Homework Equations
∆y = L λ/d
The Attempt at a Solution
Given:
Line density = 1500lines/cm
L = 1.5m
λ = 760nm = 7.6 x10-7m
Required: ∆y
Solution:
d= 1.0cm / 1500lines
d= 6.67 x10-6m∆y = L λ/d
∆y = (1.5m)(7.6 x10-7m) / (6.67 x10-6m)
∆y = 0.1709m
∆y = 1.7 x10-1mTherefore, the distance between adjacent bright fringes is 1.7 x10-1m.
I'm pretty confident with this answer, but I'm not sure if I determined the value of d correctly, (is it always 1.0cm/# of lines?) Also should the final answer be presented as 1.7 x10-1m, or 0.1709m, as it is not a very small number, as is usually the answer (such as 1.7 x10-6). Any feedback would be a big help.