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Two light sources against a wall

  • Thread starter menco
  • Start date
  • #1
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0

Homework Statement



Two light sources half a millimetre apart with a wavelength of 550nm shine on a wall exactly 50cm away. What is the distance between the centre point on the wall and the 10th bright spot out?

Homework Equations



x=nLv/d


The Attempt at a Solution



x=10x0.5x(5.5x10^-7)/0.0005
= 0.0055m = 5.5mm
 

Answers and Replies

  • #2
Delphi51
Homework Helper
3,407
10
I agree with that answer. The assumption that the angle is sufficiently small so that nλ = d*sin(θ) equals dx/L appears to be reasonable. Working it out with the exact nλ = d*sin(θ) yields x = 5.5003 mm.
 

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