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? 發問於 科學及數學其他 - 科學 · 1 十年前

physics(blooming of lens)

AL phy paperII MC Q15

A coating material of refractive index 1.25 is used for the blooming of a lens having a larger refractive index. For narmal incidence, if green light is to be transmitted in its greatest amount through the lens, which of the following thicknesses of the coating would do?

(Given: wavelength of green light in air is 550nm)

(1) 137.5nm

(2) 220nm

(3) 330nm

A. (1) only

B. (3) only

C. (1) and (2) only

D. (2) and (3) only

E. (1), (2) and (3)

1 個解答

評分
  • 1 十年前
    最愛解答

    By blooming of lens,

    2nd = (m - 1/2)入, for m is a positive integer

    d = (m - 1/2)入/2n

    Thickness of the lens, d = (m - 1/2)(550 X 10^-9)/2(1.25) = 2.2 X 10^-7(m - 1/2)

    Put m = 1, d = 1.1 X 10^-7 m

    Put m = 2, d = 3.3 X 10^-7 m

    And put m = 3 or more, the value of d is larger than the three options.

    So, The answer is B. (3) only

    資料來源: Physics king
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