Задача 40841.

A plane light wave is incident normal to the diaphragm with a hole of variable radius. In parallel, the diaphragm is the screen. It is known that for this geometry hole opens the first Fresnel zone for a point P on the screen. How many times should increase the radius of the hole to the point emerged: a) a first minimum; b) a second maximum?

Detailed solution with a short recording conditions, laws and formulas used in the decision, the withdrawal of the calculation formula and the answer.
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