Chapter Unit - 2 : Light[Refraction and Total internal Reflection of Light] - Frank Solutions for Class 10 Physics ICSE
In ICSE Class 10, Physics is one of the most important subjects, as the fundamentals learnt also assist students to clear the competitive exams like IIT-JEE and NEET. TopperLearning provides ICSE Class 10 Physics students with robust study materials to help them to score well in the examination. Our study materials are created by subject experts and provide better insight on how to prepare for the ICSE Class 10 Physics examination.
Chapter 2 - Light[Refraction and Total internal Reflection of Light] Excercise 102
(i) Angle of incidence versus angle of reflection,
(ii) Sine of angle of incidence versus sine of angle of refraction,
(iii) Angle of incidence versus angle of refraction.
For e.g. if light travels from air to water along a certain path, then if the path is reversed while travelling from water to air, it will follow exactly the same path.
index of air with respect to water
n21 = Speed of light (v1) in first medium / speed of light (v2) in second medium
The refractive index of glass is typically around 1.5, meaning that light in glass travels at
c / 1.5 = 200,000 km/s. A low value of refractive index also indicates a large critical angle at the glass-air interface.
(i) The angle of incidence
(ii) The material of prism
(iii) The angle of prism
(iv) The colour of wavelength of light used.
(a) Glass (b) Water
(c) Diamond (d) Ruby
(a) 00 (b) 450
(c) 600 (d) 900
A ray of light passes from air to water. In fig. 39, which of the ray A, B, C and D is the correct refracted ray?
Ray B is the correct refracted ray because a ray of light travelling from air (rarer medium) to water (denser medium) will bend towards the normal.
In the fig. 40, name the ray which represents the correct path of light while passing through a glass block.
The correct path is that of ray 'B'.
Chapter Unit - 2 - Light[Refraction and Total internal Reflection of Light] Excercise 103
In the fig. 41, PO is a ray of light incident on a rectangular glass block.
(a) Complete the path of the ray through the block.
(b) In the diagram, mark the angle of incidence (i) and the angle of refraction (r) at the first interface. How is the refractive index of glass related to the angles I and r?
(c) Mark angle of emergence by the letter e. How are the angles i and e related?
(d) Which two rays are parallel to each other? Name them.
(e) Indicate in the diagram the lateral displacement between the emergent ray and the incident ray.
(i) The colour (or wavelength) of light.
(ii) The temperature (on changing the temperature of medium, its refractive index changes).
(i) more than 45o for red light.
(ii) less than 45o for blue light.
Fill in the blanks to complete the following sentences:
(a) When light travels from a rarer to a denser medium, it bends ...........
(b) When light travels from a denser to a rarer medium, it bends ............
(c) The refractive index of glass with respect to air is 3/2. The refractive index of air with respect to glass will be...........
(a) towards the normal.
(b) away from the normal.
Total internal reflection: When a ray of light travelling from an optically denser medium to an optically rare medium is incident at an angle greater than the critical angle for the pair of media in contact, the ray is totally reflected back into the denser medium. This phenomenon is referred as total internal reflection.
The two necessary conditions for total internal reflection to take place are:
1. The light ray must proceed from denser to rarer medium.
2. Angle of incidence in denser medium should be greater than the critical angle for the pair of media in contact.
Relation between critical angle and r.i.: The critical angle can thus be calculated by taking the inverse-sine ratio of speed of light in denser medium and the speed of light in rarer.
Ray diagram showing refraction of light through a glass slab:
(i) When total internal reflection occurs, the entire light (100%) is reflected back into the denser medium, whereas in ordinary reflection from plane mirror, some light is refracted or absorbed (i.e. reflection is partial).
(ii) Total reflecting prism gives a much brighter image than that obtained by using the plane mirror.
Key Features of Study Materials for ICSE Class 10 Physics:
- According to the latest ICSE syllabus
- Prepared by subject matter experts
- Helpful for quick revision
- Free solved sample papers available
- Significantly improve your marks
Kindly Sign up for a personalised experience
- Ask Study Doubts
- Sample Papers
- Past Year Papers
- Textbook Solutions
Verify mobile number
Enter the OTP sent to your number