Re: [題目] 雙狹縫干涉
※ 引述《hbkhhhdx2006 (大T)》之銘言：
: [領域] 雙狹縫干涉
: [來源] 課本習題
: [題目] Monochromatic light is directed on a double slit. A light meter is
: placed to the right of the slits. When slit S2 is closed, the
: light intensity at the location of the meter is I1. When slit S2 is
: closed the light intensity is I2.
: (a) What is the light intensity "I" when both slits are open if
: x1-x2=λ?
: (b) What is "I" if x1-x2=(1/2)λ?
: Assume that the size of the slits is smaller than the wavelengh so
: that the slits can be considered to be point sources.
: 附圖：http://ppt.cc/DYgQ
: [瓶頸] 這題我完全不知道怎麼解
: 原文書上沒有提到這種東西以前也沒學過
: 答案是 (a) I1-I2+2(I1I2)^(1/2) (b) I1+I2-2(I1I2^(1/2)
因為光強度與振幅平方成正比，故可令
I1 = k(A1)^2 和 I2 = k(A2)^2
當 x1 - x2 = λ，也就是完全建設性干涉，其振幅 A = |A1 + A2|
總強度 I = k(A1 + A2)^2 = k(A1)^2 + k(A2)^2 + 2k(A1)(A2)
= I1 + I2 + 2[(I1)(I2)]^(1/2)
當 x1 - x2 = (1/2)λ，也就是完全破壞性干涉，其振幅 A = |A1 - A2|
總強度 I = k(A1 - A2)^2 = k(A1)^2 + k(A2)^2 - 2k(A1)(A2)
= I1 + I2 - 2[(I1)(I2)]^(1/2)
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03/09 23:47, , 1F
03/09 23:47, 1F
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