# Question Video: Relating the Diffraction Angles of Waves Passing through an Aperture to Its Width Physics • 9th Grade

Which of the following conditions results in the largest diffraction angle when a wave passes through a gap? [A] The gap’s width is equal to the amplitude of the wave. [B] The gap’s width is equal to the wavelength of the wave. [C] The gap’s width is equal to the speed of the wave multiplied by the periodic time of the wave. [D] The gap’s width is equal to the speed of the wave multiplied by the amplitude of the wave. [E] The gap’s width is equal to the speed of the wave multiplied by the frequency of the wave.

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### Video Transcript

Which of the following conditions results in the largest diffraction angle when a wave passes through a gap? 1) the gap’s width is equal to the amplitude of the wave, 2) the gap’s width is equal to the wavelength of the wave, 3) the gap’s width is equal to the speed of the wave multiplied by the periodic time of the wave, 4) the gap’s width is equal to the speed of the wave multiplied by the amplitude of the wave, 5) the gap’s width is equal to the speed of the wave multiplied by the frequency of the wave.

Okay, so in this question, what we’ve got is a wave which we can say is travelling in this direction and it passes through a gap and gets diffracted. We need to find the condition for which the diffraction is going to be as large as possible.

Now, this is a piece of information that we need to know. We need to know that the diffraction of the wave is going to be as large as possible when the size of the gap is equal to the wavelength of the wave. Now, the reasoning behind this is rather complicated. But this is just something that we need to know.

So statement two is the answer to our question. The gap’s width is equal to the wavelength of the wave.