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Refraction Of Light 
Exercise 
Q. 1. Fill in the blanks and Explain the completed sentences. 
 
a. Refractive index depends on the ............. of light. 
b. The change in ................ of light rays while going from one medium to another 
is called refraction. 
Answer : (a) Refractive index depends on the velocity of light. 
 
Explanation: The velocity of light is different in different medium. Speed of light is more 
in rarer medium as compared to denser medium. The medium in which speed of light is 
less, higher is the refractive index of that medium. 
(b) The change in direction of light rays while going from one medium to another is 
called refraction. 
Explanation: When a ray of light passes from one medium to another it changes its 
direction as speed of light is different in different medium. This phenomenon of light is 
called refraction. 
Q. 2. A. Prove the following statements. 
 
If the angle of incidence and angle of emergence of a light ray falling on a glass 
slab are i and e respectively, prove that, i = e. 
Answer : i. Take a rectangular glass slab PQRS as shown in below figure. 
 
ii. Draw an incident ray AO and a normal NN’. Measure the angle of incidence i. 
iii. As light ray travels from air to glass i.e. rarer to denser medium it bends towards the 
normal. So refracted ray OB bend towards normal. 
iv. Again light ray passes from glass to air at surface SR so emergent ray BC bends 
away from normal N1N1’. Measure the angle e. 
v. We will find that angle of incidence i = angle of emergence e. We will also observed 
that incident ray and emergent ray are parallel to each other since angle of incidence i = 
angle of emergence e. 
 
 
Page 2


Refraction Of Light 
Exercise 
Q. 1. Fill in the blanks and Explain the completed sentences. 
 
a. Refractive index depends on the ............. of light. 
b. The change in ................ of light rays while going from one medium to another 
is called refraction. 
Answer : (a) Refractive index depends on the velocity of light. 
 
Explanation: The velocity of light is different in different medium. Speed of light is more 
in rarer medium as compared to denser medium. The medium in which speed of light is 
less, higher is the refractive index of that medium. 
(b) The change in direction of light rays while going from one medium to another is 
called refraction. 
Explanation: When a ray of light passes from one medium to another it changes its 
direction as speed of light is different in different medium. This phenomenon of light is 
called refraction. 
Q. 2. A. Prove the following statements. 
 
If the angle of incidence and angle of emergence of a light ray falling on a glass 
slab are i and e respectively, prove that, i = e. 
Answer : i. Take a rectangular glass slab PQRS as shown in below figure. 
 
ii. Draw an incident ray AO and a normal NN’. Measure the angle of incidence i. 
iii. As light ray travels from air to glass i.e. rarer to denser medium it bends towards the 
normal. So refracted ray OB bend towards normal. 
iv. Again light ray passes from glass to air at surface SR so emergent ray BC bends 
away from normal N1N1’. Measure the angle e. 
v. We will find that angle of incidence i = angle of emergence e. We will also observed 
that incident ray and emergent ray are parallel to each other since angle of incidence i = 
angle of emergence e. 
 
 
 
Q. 2. B. Prove the following statements. 
A rainbow is the combined effect of the refraction, dispersion, and total internal 
reflection of light. 
Answer : Rainbow is a natural spectrum appearing in the sky after a rain shower. It is 
formed due to combination of phenomenon like refraction, dispersion and total internal 
reflection of light. Water droplets act like small prisms which refract and disperse the 
incident sunlight. Then they reflect it internally and finally again refract it to form rainbow 
in the sky. 
 
 
Q. 3. A. Mark the correct answer in the following questions. 
 
What is the reason for the twinkling of stars? 
A. Explosions occurring in stars from time to time 
 
Page 3


Refraction Of Light 
Exercise 
Q. 1. Fill in the blanks and Explain the completed sentences. 
 
a. Refractive index depends on the ............. of light. 
b. The change in ................ of light rays while going from one medium to another 
is called refraction. 
Answer : (a) Refractive index depends on the velocity of light. 
 
Explanation: The velocity of light is different in different medium. Speed of light is more 
in rarer medium as compared to denser medium. The medium in which speed of light is 
less, higher is the refractive index of that medium. 
(b) The change in direction of light rays while going from one medium to another is 
called refraction. 
Explanation: When a ray of light passes from one medium to another it changes its 
direction as speed of light is different in different medium. This phenomenon of light is 
called refraction. 
Q. 2. A. Prove the following statements. 
 
If the angle of incidence and angle of emergence of a light ray falling on a glass 
slab are i and e respectively, prove that, i = e. 
Answer : i. Take a rectangular glass slab PQRS as shown in below figure. 
 
ii. Draw an incident ray AO and a normal NN’. Measure the angle of incidence i. 
iii. As light ray travels from air to glass i.e. rarer to denser medium it bends towards the 
normal. So refracted ray OB bend towards normal. 
iv. Again light ray passes from glass to air at surface SR so emergent ray BC bends 
away from normal N1N1’. Measure the angle e. 
v. We will find that angle of incidence i = angle of emergence e. We will also observed 
that incident ray and emergent ray are parallel to each other since angle of incidence i = 
angle of emergence e. 
 
 
 
Q. 2. B. Prove the following statements. 
A rainbow is the combined effect of the refraction, dispersion, and total internal 
reflection of light. 
Answer : Rainbow is a natural spectrum appearing in the sky after a rain shower. It is 
formed due to combination of phenomenon like refraction, dispersion and total internal 
reflection of light. Water droplets act like small prisms which refract and disperse the 
incident sunlight. Then they reflect it internally and finally again refract it to form rainbow 
in the sky. 
 
 
Q. 3. A. Mark the correct answer in the following questions. 
 
What is the reason for the twinkling of stars? 
A. Explosions occurring in stars from time to time 
 
B. Absorption of light in the earth’s atmosphere 
C. Motion of stars 
D. Changing refractive index of the atmospheric gases 
Answer : Stars are point source of light very far from us. Light rays from stars passes 
through various layers of atmosphere whose refractive index goes on changing due to 
mobility of air, temperature and various gases present in air. So light suffer refraction 
when reaches to our eye and we see apparent position of star. Due to continuous 
change in refractive index of air sometimes star appear to us as bright or dim which 
appears to us as twinkling of star. 
 
Q. 3. B. Mark the correct answer in the following questions. 
 
We can see the Sun even when it is little below the horizon because of 
A. Reflection of light 
 
B. Refraction of light 
C. Dispersion of light 
D. Absorption of light 
Answer : During sunrise when sun is little below horizon the light rays move through 
different refractive indices of air and get bends towards the normal undergoing 
refraction so we see the apparent position of the sun S’. Thus even though the sun is 
below the horizon we can see the sunrise. 
 
Page 4


Refraction Of Light 
Exercise 
Q. 1. Fill in the blanks and Explain the completed sentences. 
 
a. Refractive index depends on the ............. of light. 
b. The change in ................ of light rays while going from one medium to another 
is called refraction. 
Answer : (a) Refractive index depends on the velocity of light. 
 
Explanation: The velocity of light is different in different medium. Speed of light is more 
in rarer medium as compared to denser medium. The medium in which speed of light is 
less, higher is the refractive index of that medium. 
(b) The change in direction of light rays while going from one medium to another is 
called refraction. 
Explanation: When a ray of light passes from one medium to another it changes its 
direction as speed of light is different in different medium. This phenomenon of light is 
called refraction. 
Q. 2. A. Prove the following statements. 
 
If the angle of incidence and angle of emergence of a light ray falling on a glass 
slab are i and e respectively, prove that, i = e. 
Answer : i. Take a rectangular glass slab PQRS as shown in below figure. 
 
ii. Draw an incident ray AO and a normal NN’. Measure the angle of incidence i. 
iii. As light ray travels from air to glass i.e. rarer to denser medium it bends towards the 
normal. So refracted ray OB bend towards normal. 
iv. Again light ray passes from glass to air at surface SR so emergent ray BC bends 
away from normal N1N1’. Measure the angle e. 
v. We will find that angle of incidence i = angle of emergence e. We will also observed 
that incident ray and emergent ray are parallel to each other since angle of incidence i = 
angle of emergence e. 
 
 
 
Q. 2. B. Prove the following statements. 
A rainbow is the combined effect of the refraction, dispersion, and total internal 
reflection of light. 
Answer : Rainbow is a natural spectrum appearing in the sky after a rain shower. It is 
formed due to combination of phenomenon like refraction, dispersion and total internal 
reflection of light. Water droplets act like small prisms which refract and disperse the 
incident sunlight. Then they reflect it internally and finally again refract it to form rainbow 
in the sky. 
 
 
Q. 3. A. Mark the correct answer in the following questions. 
 
What is the reason for the twinkling of stars? 
A. Explosions occurring in stars from time to time 
 
B. Absorption of light in the earth’s atmosphere 
C. Motion of stars 
D. Changing refractive index of the atmospheric gases 
Answer : Stars are point source of light very far from us. Light rays from stars passes 
through various layers of atmosphere whose refractive index goes on changing due to 
mobility of air, temperature and various gases present in air. So light suffer refraction 
when reaches to our eye and we see apparent position of star. Due to continuous 
change in refractive index of air sometimes star appear to us as bright or dim which 
appears to us as twinkling of star. 
 
Q. 3. B. Mark the correct answer in the following questions. 
 
We can see the Sun even when it is little below the horizon because of 
A. Reflection of light 
 
B. Refraction of light 
C. Dispersion of light 
D. Absorption of light 
Answer : During sunrise when sun is little below horizon the light rays move through 
different refractive indices of air and get bends towards the normal undergoing 
refraction so we see the apparent position of the sun S’. Thus even though the sun is 
below the horizon we can see the sunrise. 
 
 
Q. 3. C. Mark the correct answer in the following questions. 
 
If the refractive index of glass with respect to air is 3/2, what is the refractive 
index of air with respect to glass? 
 
Answer : Since refractive index of medium 2 with respect to medium 1 = 1/refractive 
index of medium 1 with respect to refractive index of medium 2. So if refractive index of 
glass with respect to air is 3/2 so refractive index of air with respect to glass = 
1
3
2
 = 
2
3
 
Q. 4. A. Solve the following examples. 
 
If the speed of light in a medium is 1.5 x 10
8
 m/s, what is the absolute refractive 
index of the medium? 
Answer : Absolute refractive index of medium is with respect to air. 
 
Page 5


Refraction Of Light 
Exercise 
Q. 1. Fill in the blanks and Explain the completed sentences. 
 
a. Refractive index depends on the ............. of light. 
b. The change in ................ of light rays while going from one medium to another 
is called refraction. 
Answer : (a) Refractive index depends on the velocity of light. 
 
Explanation: The velocity of light is different in different medium. Speed of light is more 
in rarer medium as compared to denser medium. The medium in which speed of light is 
less, higher is the refractive index of that medium. 
(b) The change in direction of light rays while going from one medium to another is 
called refraction. 
Explanation: When a ray of light passes from one medium to another it changes its 
direction as speed of light is different in different medium. This phenomenon of light is 
called refraction. 
Q. 2. A. Prove the following statements. 
 
If the angle of incidence and angle of emergence of a light ray falling on a glass 
slab are i and e respectively, prove that, i = e. 
Answer : i. Take a rectangular glass slab PQRS as shown in below figure. 
 
ii. Draw an incident ray AO and a normal NN’. Measure the angle of incidence i. 
iii. As light ray travels from air to glass i.e. rarer to denser medium it bends towards the 
normal. So refracted ray OB bend towards normal. 
iv. Again light ray passes from glass to air at surface SR so emergent ray BC bends 
away from normal N1N1’. Measure the angle e. 
v. We will find that angle of incidence i = angle of emergence e. We will also observed 
that incident ray and emergent ray are parallel to each other since angle of incidence i = 
angle of emergence e. 
 
 
 
Q. 2. B. Prove the following statements. 
A rainbow is the combined effect of the refraction, dispersion, and total internal 
reflection of light. 
Answer : Rainbow is a natural spectrum appearing in the sky after a rain shower. It is 
formed due to combination of phenomenon like refraction, dispersion and total internal 
reflection of light. Water droplets act like small prisms which refract and disperse the 
incident sunlight. Then they reflect it internally and finally again refract it to form rainbow 
in the sky. 
 
 
Q. 3. A. Mark the correct answer in the following questions. 
 
What is the reason for the twinkling of stars? 
A. Explosions occurring in stars from time to time 
 
B. Absorption of light in the earth’s atmosphere 
C. Motion of stars 
D. Changing refractive index of the atmospheric gases 
Answer : Stars are point source of light very far from us. Light rays from stars passes 
through various layers of atmosphere whose refractive index goes on changing due to 
mobility of air, temperature and various gases present in air. So light suffer refraction 
when reaches to our eye and we see apparent position of star. Due to continuous 
change in refractive index of air sometimes star appear to us as bright or dim which 
appears to us as twinkling of star. 
 
Q. 3. B. Mark the correct answer in the following questions. 
 
We can see the Sun even when it is little below the horizon because of 
A. Reflection of light 
 
B. Refraction of light 
C. Dispersion of light 
D. Absorption of light 
Answer : During sunrise when sun is little below horizon the light rays move through 
different refractive indices of air and get bends towards the normal undergoing 
refraction so we see the apparent position of the sun S’. Thus even though the sun is 
below the horizon we can see the sunrise. 
 
 
Q. 3. C. Mark the correct answer in the following questions. 
 
If the refractive index of glass with respect to air is 3/2, what is the refractive 
index of air with respect to glass? 
 
Answer : Since refractive index of medium 2 with respect to medium 1 = 1/refractive 
index of medium 1 with respect to refractive index of medium 2. So if refractive index of 
glass with respect to air is 3/2 so refractive index of air with respect to glass = 
1
3
2
 = 
2
3
 
Q. 4. A. Solve the following examples. 
 
If the speed of light in a medium is 1.5 x 10
8
 m/s, what is the absolute refractive 
index of the medium? 
Answer : Absolute refractive index of medium is with respect to air. 
 
So absolute refractive index of medium µ =  
Speed of light in air = 3 x 10
8
 m/s 
Speed of light in the given medium = 1.5 x 10
8
 m/s 
Absolute refractive index of medium µ =  
So µ = 2 
Q. 4. B. Solve the following examples. 
 
If the absolute refractive indices of glass and water are 3/2 and 4/3 respectively, 
what is the refractive index of glass with respect to water? 
Answer : Refractive Index of glass = 3/2 
Refractive index of water = 4/3 
So refractive index of glass with respect to water =  
=  
= 9/8 
So refractive index of glass with respect to water = 9/8 
 
 
 
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FAQs on Textbook Solutions: Refraction of Light - Science and Technology Class 10 (Maharashtra SSC Board)

1. What is refraction of light and how does it occur?
Ans. Refraction of light is the bending of light rays as they pass from one medium to another with a different density. This change in speed as light enters a new medium causes the light to change direction. For example, when light travels from air into water, it slows down and bends towards the normal line (an imaginary line perpendicular to the surface at the point of entry).
2. What are the laws of refraction?
Ans. The laws of refraction include two main principles: 1. The incident ray, the refracted ray, and the normal all lie in the same plane. 2. The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant for any two given media. This is known as Snell's Law and can be mathematically expressed as sin(i)/sin(r) = n, where i is the angle of incidence, r is the angle of refraction, and n is the refractive index of the two media.
3. How can the refractive index of a medium be determined?
Ans. The refractive index of a medium can be determined using Snell's Law. By measuring the angle of incidence and the angle of refraction when light passes from air into the medium, the refractive index can be calculated using the formula n = sin(i)/sin(r). Alternatively, it can also be found by comparing the speed of light in a vacuum to the speed of light in the medium.
4. What is total internal reflection and under what conditions does it occur?
Ans. Total internal reflection is a phenomenon that occurs when a light ray travels from a denser medium to a rarer medium at an angle greater than the critical angle. Under these conditions, all the light is reflected back into the denser medium instead of passing into the rarer one. The critical angle is specific to the pair of media and can be calculated using the refractive indices of the two materials.
5. What are some practical applications of refraction of light?
Ans. Refraction of light has numerous practical applications, including: - Lenses in glasses, microscopes, and cameras, which use refraction to focus light and form clear images. - Fiber optics, where light is transmitted through thin strands of glass or plastic using total internal reflection. - Prisms, which disperse light into its constituent colors, are used in various optical instruments.
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