ch36-p039

# ch36-p039 - 39. (a) The angular positions of the bright...

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39. (a) The angular positions θ of the bright interference fringes are given by d sin = m λ , where d is the slit separation, λ is the wavelength, and m is an integer. The first diffraction minimum occurs at the angle 1 given by a sin 1 = λ , where a is the slit width. The diffraction peak extends from – 1 to + 1 , so we should count the number of values of m for which – 1 < < + 1 , or, equivalently, the number of values of m for which – sin 1 < sin < + sin 1 . This means – 1/ a < m / d < 1/ a or – d / a < m < +d / a . Now d / a = (0.150 × 10 –3 m)/(30.0 × 10 –6 m) = 5.00, so the values of m are m = –4, –3, –2, –1, 0, +1, +2, +3, and +4. There are 9 fringes.
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## This note was uploaded on 06/03/2011 for the course PHY 2049 taught by Professor Any during the Spring '08 term at University of Florida.

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