Please show work and explain. Answer is already given. Thank You. Light with wav
ID: 1303754 • Letter: P
Question
Please show work and explain. Answer is already given. Thank You. Light with wavelengths from 400 nm to 750 nm is involved in thin film interference with oil on water. At what minimum thickness will there be constructive interference for green light? (550nm) 98.2 nm 137.5 nm 196.4 nm 275.0 nm 392.9 nm At what minimum thickness will there be destructive interference for blue light? (430nm) 80.4 nm 112.5 nm 160.7 nm 225 nm 321.4 nm If there was water above the thin film also (instead of air), how would the previous answer (to #10) change? It would increase. It would decrease. It would remain the same.Explanation / Answer
Number 7)
Apply 2nt = (m + .5)(wavelength)
2(1.4)(t) = .5(550 X 10-9)
t = 9.82 X 10-8 m That is 98.2 nm
Number 8
Apply 2nt = m(wavelength)
2(1.4)(t) = (1)(450 X 10-9)
t = 1.607 X 10-7 m which is 160.7 nm
Number 9)
The answer would remain the same since the index of refraction of the oil remains the same and that is the value used in the equation. Additionally, just like air, the index of water is less than oil. (Note, the answer would only change if there was an index value greater than oil placed instead of the air.)