- #1
StudentofPhysics
- 67
- 0
1. A nonreflective coating (n = 1.24) covers the glass (n = 1.52) of a camera lens. Assuming that the coating prevents reflection of yellow-green light (wavelength in vacuum = 564 nm), determine the minimum nonzero thickness that the coating can have.
2. wavelength of the light in the coating = wavelngth of light / n of coating
desructive interference: 2t = (1,2...) wavelngth coating
t=thickness
3. OK the wavelngth of the light through the coating is: 564/1.24 = 454.84
I figured maybe that was all i needed and attempted to find t.
2t=1(454.84)
t= 227.42
this was not correct, so I next proceded to find the wavelength once through the film to the glass:
454.84/1.52 = 299.24 nm
The destructive interference for this is:
2t = (1) 299.24
t= 149.62 nm
This too was incorrect.
I even tried plugging in the original wavelength of 564 nm with the n of glass; 1.52, then solving for t. This gave me:
564/1.52 = 371.05
2t= (1) 371.05
t= 185.53
None of these were correct.
Any thoughts on where am I going wrong?
2. wavelength of the light in the coating = wavelngth of light / n of coating
desructive interference: 2t = (1,2...) wavelngth coating
t=thickness
3. OK the wavelngth of the light through the coating is: 564/1.24 = 454.84
I figured maybe that was all i needed and attempted to find t.
2t=1(454.84)
t= 227.42
this was not correct, so I next proceded to find the wavelength once through the film to the glass:
454.84/1.52 = 299.24 nm
The destructive interference for this is:
2t = (1) 299.24
t= 149.62 nm
This too was incorrect.
I even tried plugging in the original wavelength of 564 nm with the n of glass; 1.52, then solving for t. This gave me:
564/1.52 = 371.05
2t= (1) 371.05
t= 185.53
None of these were correct.
Any thoughts on where am I going wrong?