A soap film of refractive index 4/3 and thickness `1.5xx10^(-4)`cm is illuminated by white light incident at angle `45^(@)`. The reflected light is examined by a spectroscope in which a dark band corresponding to the wavelength `5xx10^(-5)` cm is found. Find the order of the interference band
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A soap flim of thickness `0.3 mu m` appears dark when seen by the refracted light of wavelength `580 nm`. What is the index of refraction of the soap
Correct Answer - 1.45 The path difference is `2mu t`. Now for destructive interface it can be `2mut=(lambda)/(2)` or `(3lambda)/(2)` or `(5lambda)/(2)` and so on……… `mu=(lambda)/(4 t),(3lambda)/(4 t),(5lambda)/(4 t)……..` `=(580xx10^(-9))/(4xx0.3xx10^(-6)) ,...
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A parallel beam of light of wavelenght `560 nm` falls on a film of oil (refractive index `=1.4`). What should be the minimum thickness of the film so
Correct Answer - `100 mm`
2 Answers 1 views
White light is incident normally on a glass plate (in air) of thickness `500 nm` and refractive index of `1.5`. The wavelength (in `nm`) in the visibl
Correct Answer - B For strong reflection. `2mut=(lambda)/(2),(3lambda)/(2),(5lambda)/(2).....rArr lambda=4mut,(4mut)/(3),(4mut)/(5),(4mut)/(7).....` `rArr 3000 nm. 1000 nm, 600 nm, 333 nm.` `rArr` only option is `600 nm`.
2 Answers 1 views
A parallel beam of white light falls from air on a thin film whose refractive index is `sqrt ( 3)` . The medium on both sides of the film is air. The
Correct Answer - 100nm
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A thin film having refractive index` mu" = 1.5"` has air on both sides. It is illuminated by white light falling normally on it. Analysis of the refle
Correct Answer - (a)900 nm (b)415nm ,491nm,600nm,771nm
2 Answers 1 views
A thin film of thickness `4xx10^(-5)` cm and `mu`=1.5 is iluminated by white light incident normal to its surface. What wavelength in the visible rang
Correct Answer - 4800 Å
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White light is incident normally on a plane parallel thin film of µ=1.5. Find the minimum thickness of the film for which light of `lamda`=4000 Å is a
Correct Answer - `1.33xx10^(-7)`m
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White light is incident on a soap film at an angle of `sin^(-1(4)/(5))` and the reflected light on examination by the spectroscope shows dark bands. T
Correct Answer - `1.716xx10^(-3)`cm
2 Answers 10 views
A soap bubble of µ=4/3 is illuminated by white light incident at an angle of `30^(@)`. The transmittedlight is examined by a spectroscope and bright b
Correct Answer - `2.4xx10^(-7)`m
2 Answers 1 views
A ray of light is incident on a glass plate of refractive index 1.54. If the reflected ray is completely plane polarised, find (i) angle of incidence
Correct Answer - (i) `57^(@)` (ii) `33^(@)` (iii) `40.5 ^(@)`
2 Answers 1 views