Two closely spaced parallel glass plates are separated by 977 nm.What wavelength light source in the visible region (390 nm to 710 nm)will experience maximum transmission through the two plates?
A)651 nm
B)695 nm
C)655 nm
D)618 nm
E)601 nm

Question

Two closely spaced parallel glass plates are separated by 977 nm.What wavelength light source in the visible region (390 nm to 710 nm)will experience maximum transmission through the two plates?
A)651 nm
B)695 nm
C)655 nm
D)618 nm
E)​601 nm

Quizplus · Accepted Answer

The condition for maximum transmission (constructive interference) in thin film interference is when the path difference is an integer multiple of the wavelength. For two closely spaced plates, this occurs when the separation is an integer multiple of half the wavelength. Here, 977 nm is approximately 1.5 times 651 nm, satisfying the condition for constructive interference.

Two Closely Spaced Parallel Glass Plates Are Separated by 977