Green light of mercury has a wavelength of 5 .5 × 10 − 7 m in air. What is its frequency in MHz and period in s ?

Given wavelength of light λ = 5 . 5 × 10 - 7 m Assume velocity of light in air c = 3 × 10 8 m / s As the velocity is given by c = ν . λ where ν =frequency Putting the values in the formula, we have 3 × 10 8 = 5 . 5 × 10 - 7 × ν or ν = 3 . 0 × 10 8 5 . 5 × 10 - 7 = 5 . 45 × 10 14 Hz As time period = 1 frequenc y = 1 5 . 45 × 10 14 = 1 . 83 × 10 - 15 or 1 . 83 × 10 - 9 μs .

Green light of mercury has a wavelength of 5 .5 × 10 − 7 m in air. What is its wavelength In glass, if n glass = 1 .5 ?

Given the wavelength of light in air= λ a = 5 . 5 × 10 - 7 m Refractive index of glass = n g = 1 . 5 BY Snell's law, the refractive index is given by : n = s p e e d o f l i g h t i n a i r s p e e d o f l i g h t i n m e d i u m = ν λ a ν λ g where ν = frequency of light, which is same in both media. Substituting the values, we have, 1 . 5 = 5 . 5 × 10 - 7 λ g gives λ g = 5 . 5 × 10 - 7 1 . 5 = 3 . 67 × 10 - 7 m .

What is the geometrical shape of the wavefront for light emerging out of a convex lens when a point-source is placed at the focus of the lens?

The shape of the wavefront in case of a light emerging out of a convex lens when a point source is placed at its focus is a parallel wave front as shown in the figure. The light from the source at the focus of a lens will emerge parallel and will form a plane wave front following the Huygens' principle.

E M B I B E

ISC Physics Class 12, Part-2>Chapter 6 - Wave Nature of Light : Huygens' Principle>QUESTIONS>Q 5

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The index of refraction of glass for violet light is $1.665$ and for red light $1.618$ . Compute the difference in the speed of light in glass for the two colours.

Important Questions on Wave Nature of Light : Huygens' Principle

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ISC Physics Class 12, Part-2>Chapter 6 - Wave Nature of Light : Huygens' Principle>QUESTIONS>Q 6

The refractive index of glass is $1.5$ and that of water is $1.3$ . If the speed of light in water is $2 .25 \times 10^{8} {ms}^{- 1}$ , find the speed in glass.

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ISC Physics Class 12, Part-2>Chapter 6 - Wave Nature of Light : Huygens' Principle>QUESTIONS>Q 7

The ratio of thicknesses of the strips of two transparent media $A$ and $B$ is $6 : 4$ . If light takes the same time in passing through both of them, then what is the refractive index of $B$ with respect to $A$ ?

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ISC Physics Class 12, Part-2>Chapter 6 - Wave Nature of Light : Huygens' Principle>QUESTIONS>Q 8

Light of wavelength $4500 Å$ in vacuum enters into a glass block of refractive index $1.5$ . What is the wavelength of light in the glass block?

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ISC Physics Class 12, Part-2>Chapter 6 - Wave Nature of Light : Huygens' Principle>QUESTIONS>Q 9

Green light of mercury has a wavelength of

5 .5 \times 10^{- 7} m

in air. What is its frequency in

MHz

and period in

s

?

EASY

12th ICSE

IMPORTANT

ISC Physics Class 12, Part-2>Chapter 6 - Wave Nature of Light : Huygens' Principle>QUESTIONS>Q 9

Green light of mercury has a wavelength of

5 .5 \times 10^{- 7} m

in air. What is its wavelength In glass, if

n_{glass} = 1 .5

?

EASY

12th ICSE

IMPORTANT

ISC Physics Class 12, Part-2>Chapter 6 - Wave Nature of Light : Huygens' Principle>QUESTIONS>Q 10

The wavelength of monochromatic light in air is $6000 Å$ . The wavelength of this light in water is $4500 Å$ . Find out frequency of light in water.

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12th ICSE

IMPORTANT

ISC Physics Class 12, Part-2>Chapter 6 - Wave Nature of Light : Huygens' Principle>QUESTIONS>Q 10

The wavelength of monochromatic light in air is $6000 Å$ . The wavelength of this light in water is $4500 Å$ . Find out speed of light in water.

EASY

12th ICSE

IMPORTANT

ISC Physics Class 12, Part-2>Chapter 6 - Wave Nature of Light : Huygens' Principle>QUESTIONS>Q 11

Light waves of frequency $5 .0 \times 10^{14} Hz$ pass through a liquid in which the wavelength of light is found to be $4 .5 \times 10^{- 7} m$ . Find wavelength of light in vacuum.