A Metallic Sheet Has a Large Number of Parallel Slits $5.0 \mathrm {~mm}$

question 120

Multiple Choice

A metallic sheet has a large number of parallel slits, $5.0 \mathrm {~mm}$ wide and $20 \mathrm {~cm}$ apart. This sheet is used as a diffraction grating for microwaves. A wide parallel beam of microwaves is incident normally on the sheet. If the microwave wavelength is $6.0 \mathrm {~cm}$ , what is the largest angle from the normal, at which an intensity maximum occurs?

• A) \(84 ^ { \circ }\)
• B) \(64 ^ { \circ }\)
• C) \(69 ^ { \circ }\)
• D) \(79 ^ { \circ }\)
• E) \(74 ^ { \circ }\)