Deviation, Dispersion and Spectrum

Question 1

What does the first deviation of a ray of light in a prism depend on?

Answer 1

1. the angle of incidence

2. the refractive index of glass w.r.t air

Question 2

What does the second deviation of a ray of light in a prism depend on?

Answer 2

1. the angle of incidence at the second surface

2. the refractive index of air w.r.t glass

Question 3

What does the angle of incidence at the second surface inside a prism depend on?

Answer 3

The angle of the prism A

Question 4

What does the total angle of deviation depend on?

Answer 4

1. the angle of incidence at the first surface
2. the angle of the prism (A)
3. the refractive index of the material of the prism

Question 5

Why does the total angle of deviation depend on the color or wavelength of light used?

Answer 5

Because refractive index depends on the color and wavelength of light used, and angle of deviation depends on refractive index

Question 6

What happens to the emergent beam if the light entering the prism is a mixture of several colors?

Answer 6

The emergent beam too has different colors arranged in a definite order

Question 7

Why does the deviation caused by a prism increase with the decrease in the wavelength of light?

Answer 7

Since the refractive index of glass (material of the prism) increases with the decrease in wavelength of light

Question 8

Which color is deviated the most?

Answer 8

Violet color

Question 9

Which color is deviated the least?

Answer 9

Red color

Question 10

Why is violet color deviated most and red the least?

Answer 10

In glass, the speed of violet light is the least and that of red light is the most

Question 11

What produces the sensation of different colors on the retina of our eye?

Answer 11

The light of different wavelengths

Question 12

Name the characteristic of color, irrespective of its origin

Answer 12

Wavelength

Question 13

What odes it mean for wavelength to be the characteristic of color, irrespective of its origin?

Answer 13

Light of the same color obtained from different sources will have the same wavelength

Question 14

Name the subjective property of light related to its wavelength

Answer 14

Color

Question 15

Give the wavelength range of violet color

Answer 15

4000 A to 4460 A

Question 16

Give the wavelength range of red color

Answer 16

6200 A to 8000 A

Question 17

What does the letter A denote?

Answer 17

The unit Angstrom

Question 18

What is the value of 1 Angstrom in m?

Answer 18

1 A = 10^-10 m

Question 19

What is the value of 1 Angstrom in cm?

Answer 19

10^-8 cm

Question 20

What is the value of 1 nm in Angstrom?

Answer 20

1 nm = 10 A

Question 21

What is the frequency of red color?

Answer 21

3.75* 10^14 Hz

Question 22

What is the frequency of violet color?

Answer 22

7.5 * 10^14 Hz

Question 23

What is the trend in wavelength and frequency from the violet end to the red end of the spectrum?

Answer 23

The wavelength increases, and the frequency decreases

Question 24

What is the term for white light being a mixture of large number of wavelengths?

Answer 24

It is polychromatic in nature

Question 25

How many prominent colors does white light consist of?

Answer 25

Seven prominent colors

Question 26

Define dispersion

Answer 26

The phenomenon of splitting of white light by a prism into its constituent colors

Question 27

Define spectrum

Answer 27

On passing white light through a prism, the band of colors seen on a screen is called spectrum

Question 28

What is the cause of dispersion of white light?

Answer 28

The lights of different wavelengths travel with different speeds in a medium. When white light enters the first surface of a prism, light of different colors due to their different speed in glass, get deviated through different angles towards the base of the prism

Question 29

At which surface does dispersion take place?

Answer 29

At the first surface of the prism

Question 30

At which surface does deviation of light rays occur?

Answer 30

At both the surfaces of the prism