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Hard question or rigged?


https://gyazo.com/8bf6d759834c7ec2cca480891db6f4b0

I got A and C but the markscheme says C only any explanations?
Reply 1
Avatar for metrize
metrize
18
I also need help,

In general can someone say what happens when the slit is smaller, and what happens when the slit is karger?
Reply 2
Avatar for Pangol
Pangol
15
Original post by Xenon17

https://gyazo.com/8bf6d759834c7ec2cca480891db6f4b0

I got A and C but the markscheme says C only any explanations?


The angle of the first order beam will have a sine which is half of the sine of the second order beam. It is the sines that will halve, not the angles.
Original post by Pangol
The angle of the first order beam will have a sine which is half of the sine of the second order beam. It is the sines that will halve, not the angles.


Yes with that in mind i still get A and C
Reply 4
Avatar for SRBG
SRBG
Original post by Xenon17
Yes with that in mind i still get A and C


Halving angles ≠\not= Halving sin⁡θ\sin{\theta}
(edited 7 years ago)
Original post by Xenon17
Yes with that in mind i still get A and C


maybe you're thinking about a small angle approximation.
halving sin (Θ) implying halving Θ is a good approximation... but only when Θ is a small angle, the question doesn't say anything about the size of Θ (and the diagram doesn't make Θ look small tbh)

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