Abeam of microwaves with λ = 0.9 mm is incident upon a 9 cm slit. at a distance of 1.5 m from the slit, what is the approximate width of the slit's image (cm)?

3 cm

Explanation:

According to the question,

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.

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Now the approximate slit's image width is equal to width of central maxima.

And width of central maxima is twice the width from center to first maxima

So,

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Substitute all the variable in above equation.

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okay i have so many questions. but the big one here is: um wt..f is this mess? ?