# refraction & refractive index

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ABHISHEK K RB.Tech - Aerospace, Alliance University

CBSE Expert | Inventor of RocketPro6+ Years Teaching Exp | Mentored more than 5000 students

Helped 1000s of students get 10 CGPA in CBSE X

Episode 3REFRACTION & REFRACTIVE INDEX

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SERIESVIP

SERIESVIP

Answer: + 6.6 cm

Q9. The focal length of a convex mirror is 10 cm and the object distance is 20 cm. Determine the image distance

HW

SERIESVIP Q1. Beams of light are incident through the holes A and

B and emerge out of box through the holes C and D respectively as shown in the figure. Which of the following could be inside the box?

Sample paper

SERIESVIP Q1. Beams of light are incident through the holes A and

B and emerge out of box through the holes C and D respectively as shown in the figure. Which of the following could be inside the box?

A rectangular glass slab Convex lens

Concave lens A Prism

a. b.

c. d.

Sample paper

SERIESVIP Q1. Beams of light are incident through the holes A and

B and emerge out of box through the holes C and D respectively as shown in the figure. Which of the following could be inside the box?

A rectangular glass slab Convex lens

Concave lens A Prism

a. b.

c. d.

Sample paper

SERIESVIP

Q2. Given refractive indices of glass, diamond and water as 1.5, 2.42 and 1.33 respectively. In which medium does light travel (a) fastest (b) Slowest

(a) Diamond(b) water

(a) Water(b) Diamond

(a) Glass(b) Diamond

(a) Water(b) Glass

a. b.

c. d.

CBSE : 2011

SERIESVIP

Q2. Given refractive indices of glass, diamond and water as 1.5, 2.42 and 1.33 respectively. In which medium does light travel (a) fastest (b) Slowest

(a) Diamond(b) water

(a) Water(b) Diamond

(a) Glass(b) Diamond

(a) Water(b) Glass

a. b.

c. d.

CBSE : 2011

SERIESVIP

Q3. If refractive index of glass with respect to air is 1.5, then the refractive index of air with respect to glass will be:

1.77 0.667

2.5 1.5

a. b.

c. d.

Sample paper

SERIESVIP

Q3. If refractive index of glass with respect to air is 1.5, then the refractive index of air with respect to glass will be:

Sample paper

SERIESVIP

Q3. If refractive index of glass with respect to air is 1.5, then the refractive index of air with respect to glass will be:

1.77 0.667

2.5 1.5

a. b.

c. d.

Sample paper

SERIESVIP

Q4. The speed of light in a transparent medium is 0.6 times that of its speed in vacuum. What is the refractive index of the medium?

1.5 0.6

1.67 2.5

a. b.

c. d.

CBSE : 2010

SERIESVIP

Q4. The speed of light in a transparent medium is 0.6 times that of its speed in vacuum. What is the refractive index of the medium?

CBSE : 2010

SERIESVIP

Q4. The speed of light in a transparent medium is 0.6 times that of its speed in vacuum. What is the refractive index of the medium?

1.5 0.6

1.67 2.5

a. b.

c. d.

CBSE : 2010

SERIESVIP Q5. The refractive indices of water and glass (both

with respect to air) are 4/3 and 3/2 respectively. Find the refractive index of water with respect to glass.

9/8 8/9

1/2 2/1

a. b.

c. d.

CBSE : 2010

SERIESVIP Q5. The refractive indices of water and glass (both

with respect to air) are 4/3 and 3/2 respectively. Find the refractive index of water with respect to glass.

CBSE : 2010

SERIESVIP Q5. The refractive indices of water and glass (both

with respect to air) are 4/3 and 3/2 respectively. Find the refractive index of water with respect to glass.

9/8 8/9

1/2 2/1

a. b.

c. d.

CBSE : 2010

SERIESVIP

Q6. A light ray enters from medium A to medium B as shown in the figure. The refractive index of medium B relative to A will be :

Sample paper

SERIESVIP

Q6. A light ray enters from medium A to medium B as shown in the figure. The refractive index of medium B relative to A will be :

Greater than unity Less than unity

Equal to unity zero

a. b.

c. d.

Sample paper

SERIESVIP

Q6. A light ray enters from medium A to medium B as shown in the figure. The refractive index of medium B relative to A will be :

Greater than unity Less than unity

Equal to unity zero

a. b.

c. d.

Sample paper

Let’s do the Tabahi Math!!

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Let’s do the Tabahi Math!!

Coupon CodeAKPRO

Per Class Price ₹ 2159 /- ₹ 5599 /- ₹ 9199 /-

200 600 1200

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Per Class Price ₹ 11 /- ₹ 9 /- ₹ 8 /-

Lesser than Your

SERIESVIP Q7. Velocity of light in a certain medium is 2 x 108 m/s

and velocity of light in air is 3 x 108 m/s. A ray of light travelling in air, is incident on the interface of air with the said medium at an angle of 30° with the interface. What is the value of sine of angle of refraction

0.33 0.5

0.87 0.65

a. b.

c. d.

Sample paper

SERIESVIP Q7. Velocity of light in a certain medium is 2 x 108 m/s

and velocity of light in air is 3 x 108 m/s. A ray of light travelling in air, is incident on the interface of air with the said medium at an angle of 30° with the interface.What is the value of sine of angle of refraction

Sample paper

SOLUTION

V1 = 3 x 108 m/sV2 = 2 x 108 m/sn21 = (3 x 108) /(2 x 108) = 1.5

Now use snell’s law, n21 = sin i/sin r

Sin r = sin i/ n21 = sin 30 / 1.5 = 0.5/1.5 0.33

SERIESVIP Q7. Velocity of light in a certain medium is 2 x 108 m/s

and velocity of light in air is 3 x 108 m/s. A ray of light travelling in air, is incident on the interface of air with the said medium at an angle of 30° with the interface.What is the value of sine of angle of refraction

0.33 0.5

0.87 0.65

a. b.

c. d.

Sample paper

SERIESVIP

(i) 1.5 (ii) 0.65

(i) 1.18 (ii) 0.65

(i) 1.18 (ii) 0.85

(i) 0.85 (ii) 1.5

a. b.

c. d.

Q8. With respect to air, the refractive index of ice is 1.31 and that of rock salt is 1.54. Calculate (i) The refractive index of rock salt with respect to ice (ii) The refractive index of ice with respect to rock salt

Sample paper

SERIESVIP Q8. With respect to air, the refractive index of ice

is 1.31 and that of rock salt is 1.54. Calculate (i) The refractive index of rock salt with respect to ice (ii) The refractive index of ice with respect to rock salt

Sample paper

SOLUTION

refractive index of ice with respect to air = 1.31refractive index of rock with respect of air = 1.54refractive index of rock with respect to ice = 1.54/1.31 =1.18

refractive index of ice with respect to rock salt = 1.31/1.54 =0.85

SERIESVIP

(i) 1.5 (ii) 0.65

(i) 1.18 (ii) 0.65

(i) 1.18 (ii) 0.85

(i) 0.85 (ii) 1.5

a. b.

c. d.

Q8. With respect to air, the refractive index of ice is 1.31 and that of rock salt is 1.54. Calculate (i) The refractive index of rock salt with respect to ice (ii) The refractive index of ice with respect to rock salt

Sample paper

SERIESVIP

2.9 1.8

0.8 1.2

a. b.

c. d.

Q9. A ray of light travelling in oil of refractive index 1.6 falls on the oil-air interface. If the angle of incidence is 30°, what will be the value of sin of angle of refraction.

Sample paper

SERIESVIP

Q9. A ray of light travelling in oil of refractive index 1.6 falls on the oil-air interface. If the angle of incidence is 30°, what will be the value of sin of angle of refraction.

Sample paper

SOLUTION

Refractive index of oil (with respect to air) noa= 1.6So the refractive index of air with respect to oil nao = 1/noa= 1/1.6

Light travels from oil to airSnell’s law gives noa = sin i/sin r

Sin r = sin i /nao = sin30 / 1/16 = 0.5 x 1.6 = 0.8

SERIESVIP

2.9 1.8

0.8 1.2

a. b.

c. d.

Q9. A ray of light travelling in oil of refractive index 1.6 falls on the oil-air interface. If the angle of incidence is 30°, what will be the value of sin of angle of refraction.

Sample paper

SERIESVIP

Q10. The refractive index of water is 1.33 and the speed of light in air is 3 x 108 ms-1. Calculate the speed of light in water. [CBSE 2010]

HW