Class 12 ISC Physics Refraction of light at Plane Interfaces Board Questions
Here we provide Class 12 Physics important notes,board questions and predicted questions with Answers for chapter Refraction of light at Plane Interfaces. These important notes,board questions and predicted questions are based on ISC board curriculum and correspond to the most recent Class 12 Physics syllabus. By practising these Class 12 materials, students will be able to quickly review all of the ideas covered in the chapter and prepare for the Class 12 Board examinations as well as other entrance exams such as NEET and JEE.
class 12 ISC Physics Refraction of light at Plane Interfaces BoardQuestions
Refraction of light at Plane Interfaces BoardQuestions
Q1
Name the physical principle on the basis of which optical fibres work.
solutions
solutions
Q2
Where will you keep an object in front of a :
(i) convex lens in order to get a virtual and magnified image ?
(ii) concave mirror to get a real and diminished image ?
solutions
(i) convex lens in order to get a virtual and magnified image ?
(ii) concave mirror to get a real and diminished image ?
solutions
Q3
(i) Derive an expression for refraction at a single (convex) refracting surface i.e., a relation
between u, v, R, n1 ( rarer medium) , n2 ( denser medium ) where the terms have their usual meaning.
(ii) Name the phenomenon due to which the sun appears red at sunset.
solutions
(i) Laws of refraction:-
(ii) Name the phenomenon due to which the sun appears red at sunset.
solutions
(i) Laws of refraction:-
(1.) The incident ray, refracted ray and normal to the refracted surface all three lie in the same
plane.
(2.) The ratio of the sine of the angle of incidence in medium 1 to that of the angle of refraction
in medium 2 is equal to the ratio of the refractive index of medium 2 to medium 1.
n1sinθ1=n2sinθ2n1
Absolute refractive index :- Absolute refractive index of the medium is defined as the refractive
index of that medium with respect to refractive index of vacuum.
Absolute refractive index of medium
=vacuum.speed/medium,speed=c/v.............................(1.)
Refractive index of a medium :- Refractive index of the medium is defined as the refractive index of
that medium with respect to refractive index of medium 1.
Refractive index of a medium =medium2speed/medium1speed =v2/v1
By equation (1.) Hence prove that n=c/v.
(ii) Scattering of light
Q4
Name the principle on the basis of which optical fibres work.
solutions
solutions
Q5
When a light wave travels from air to glass:
(a) its wavelength decreases
(b) its wavelength increases
(c) there is no change in wavelength
(d) its frequency decreases
solutions
(a) its wavelength decreases
(b) its wavelength increases
(c) there is no change in wavelength
(d) its frequency decreases
solutions
Q6
Find critical angle for glass and water pair, given refractive index of glass is 1.62 and that of
water is 1.3.
solutions
solutions
Q7
Define critical angle for a given medium.
solutions
solutions
If a light ray travelling through a dense medium, incidence on the juncture of two medium, the second being the thinner one and the refractive ray passes along the plane separating the two media. The angle of incidence at the denser medium is the critical angle of the two media. The value of this angle depends upon the colour of the light ray and the nature of the two media. If the value of the angle of incidence is smaller than the critical angle, we get a refracted ray in the thinner medium. If the value of the angle of incidence is greater than the critical angle, we get a total internal reflection.
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