Respuesta :
Answer:
The equations are:
C. 2t=(m+12)λn(m=0,1,2,...) for constructive interference. (Here is a mistake in this equation i.e. m + 12 (wrong) and m + 1/2 (correct)). So, the correct equation for constructive interference is:
2t = (m + 1/2) λ n (m=0,1,2,...)
D. 2t=mλn(m=0,1,2,...) for destructive interference.
Explanation:
Constructive Interference occurs when two waves’ crests or troughs add together therefore, the resulting wave amplitude is equal to the sum of the each wave amplitude (in this case the amplitude of each wave is of same charge).
Destructive Interference occurs when a waves’ crest and trough cancel each other therefore, the resulting wave amplitude is zero (in this case the amplitude of each wave is oppositely charged).
When the refractive index of the medium in which the light travels is lower than the refractive index of the thin film medium then a 180° phase shift occurs.
When the light wave strikes the top surface of thin film, the wave reflects from the top surface and the reflecting light wave shifts by half of wavelength i.e. λ/2
When the light wave strikes the bottom surface of thin film then the light wave does not shift however, the light cover extra distance (2t), reflecting from the bottom surface to travel back to air.
Since, oil has refractive index (n = 1.5) which is higher than the refractive index of air (n = 1) so, when light wave strikes on the top surface of thin film of oil, the reflecting wave will shift by λ/2 (because nair < noil) and when light wave strikes on the bottom surface of thin film of oil, it will cover an extra distance to travel back to air and no wavelength shift will occur (because noil > nair).
In light of the above situation, the constructive interference of light reflected from the thin oil film is:
2t = (m + 1/2) λ n
The destructive interference of light reflected from the thin film is:
2t = m λ n
Interference is the total effect of the combination of two or more waves, which form resultant wave of greater or lower amplitude.
The equations should be used to find the minimum thickness of the oil film that satisfies the conditions of the problem is,
- C) For constructive interference (m=0,1,2,...).
[tex]2t=(m+12)\lambda n[/tex]
- D)For destructive interference (m=0,1,2,...) .
[tex]2t=m\lambda n[/tex]
What is interference?
Interference is the total effect of the combination of two or more waves, which form resultant wave of greater or lower amplitude.
- When the peaks of these two waves added together to form resultant wave of greater amplitude, then it is called the constructive interference.
- When the peaks of these two waves subtract together to form resultant wave of lower amplitude, then it is called the destructive interference.
Given information-
The minimum thickness of the oil film is [tex]t[/tex].
The wavelength of light in air is [tex]\lambda[/tex].
The index of refection of the thin film is [tex]n[/tex].
It is known that the reflection index of oil film is 1.5. This refelction index is lower then the reflection index of air ( which is 1).
The constructive interference for this case can be given as,
[tex]2t=(m+12)\lambda n[/tex]
The destructive interference for this case can be given as,
[tex]2t=m\lambda n[/tex]
Hence, the equations should be used to find the minimum thickness of the oil film that satisfies the conditions of the problem is,
- C) For constructive interference (m=0,1,2,...).
[tex]2t=(m+12)\lambda n[/tex]
- D)For destructive interference (m=0,1,2,...) .
[tex]2t=m\lambda n[/tex]
Learn more about the interference here;
https://brainly.com/question/15967698
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