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wavelenght in interference
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Wavelength of radio wave = 3x10^8/60x1^6 m = 5 m The signal is minimum when destructive interference occurs, i.e path difference = (m + 1/2)入 where m is an integer and 入 is the wavelength of the radio wave Consider the destructive interference at point A, (QA - PA) = (m + 1/2).入 -------------------- (1) But (PA) + (QA) = 15 i.e. QA = 15 - (PA) Hence, equation (1) becomes, 15 - 2(PA) = (m + 1/2).入 2(PA) = 15 - m.入 - 入/2 ----------------------- (2) Now, consider the destructive interference at point B, (QB - PB) = (m - 1 +1/2).入 -------------------- (3) But (PB) + (QB) = 15 i.e. QB = 15 - (PB) Hence, equation (3) becomes, 15 - 2(PB) = (m - 1+1/2).入 2(PB) = 15 - m.入 + 入/2 ---------------------- (4) (4) - (2): 2[(PB) - (PA)] = 入 i.e. 2(AB) = 入 = 5 m (AB) = 5/2 m = 2.5 m 2012-01-25 11:54:18 補充： Q: why is distance AB not equal to one wavelenght? A: It is clear from the calculation that between two sucessive destructive interference, there is a shift of one wavelength .... 2012-01-25 11:56:25 補充： This when PA is lengthened by 入/2, QA is automatically shortened by the same amount of 入/2, making altogether a shift of 入 for the two waves.
其他解答:
distance AB not equal to one wavelength but equal to half wavelength. because A and B are two minimum interference
wavelenght in interference
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圖片參考：http://imgcld.yimg.com/8/n/HA06578099/o/701201240045713873424190.jpg 圖片參考：http://imgcld.yimg.com/8/n/HA06578099/o/701201240045713873424191.jpg why is distance AB not equal to one wavelenght?最佳解答:
Wavelength of radio wave = 3x10^8/60x1^6 m = 5 m The signal is minimum when destructive interference occurs, i.e path difference = (m + 1/2)入 where m is an integer and 入 is the wavelength of the radio wave Consider the destructive interference at point A, (QA - PA) = (m + 1/2).入 -------------------- (1) But (PA) + (QA) = 15 i.e. QA = 15 - (PA) Hence, equation (1) becomes, 15 - 2(PA) = (m + 1/2).入 2(PA) = 15 - m.入 - 入/2 ----------------------- (2) Now, consider the destructive interference at point B, (QB - PB) = (m - 1 +1/2).入 -------------------- (3) But (PB) + (QB) = 15 i.e. QB = 15 - (PB) Hence, equation (3) becomes, 15 - 2(PB) = (m - 1+1/2).入 2(PB) = 15 - m.入 + 入/2 ---------------------- (4) (4) - (2): 2[(PB) - (PA)] = 入 i.e. 2(AB) = 入 = 5 m (AB) = 5/2 m = 2.5 m 2012-01-25 11:54:18 補充： Q: why is distance AB not equal to one wavelenght? A: It is clear from the calculation that between two sucessive destructive interference, there is a shift of one wavelength .... 2012-01-25 11:56:25 補充： This when PA is lengthened by 入/2, QA is automatically shortened by the same amount of 入/2, making altogether a shift of 入 for the two waves.
其他解答:
distance AB not equal to one wavelength but equal to half wavelength. because A and B are two minimum interference
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