Interference Questions (1 Viewer)

[sunmoonlight]

How to do this kind of question?

 

[liamkk112]

How to do this kind of question?
View attachment 43278View attachment 43279

for the second one, the path difference is given by mλ where m denotes which maximum you’re at. in this case m = 1 so the path difference is just λ pretty sure

 

[wizzkids]

How to do this kind of question?

This is the Double Slit Experiment. Go look up the Physics formula sheet and you will find a formula that links the positions of constructive interference in the interference pattern with the wavelength of light and the spacing d between the slits. Then you just have to interpret the information provided and apply the constructive interference equation, but note that the first diagram shows P1 and P2 converge at the second destructive interference fringe. The best answer is (C).
The second question is pretty trivial; all you need to know is the point where they converge is the first fringe for constructive interference. Therefore the path difference is one wavelength (B)

 

[sunmoonlight]

For the first question, isn't the formula for destructive interference (n-1/2)λ?
Also the answer for the second question is D not B

 

[sunmoonlight]

Bump

 

[liamkk112]

Bump

pretty sure the answers for the second one is wrong, it should be 1 wavelength since the path difference is m lambda and m = 1 here clearly. for the first one you can approximate to get something close to an option:

 

[wizzkids]

for the first one you can approximate to get something close to an option:

That is correct. The answer is an irrational number, but in an exam you have to choose the closest option which is (C).