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12th CBSE

IMPORTANT

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A soap film $5 \times 10^{- 5} cm$ thick is viewed at an angle of $35 °$ to the normal. Find the wavelength of light in the visible spectrum which will be absent from reflected light $(μ = 1.33) .$ Given wavelength range of the visible spectrum is $3900 Å$ to $7800 Å$ .

Important Questions on Wave Optics

MEDIUM

12th CBSE

IMPORTANT

PHYSICS A Reference Book for Class 12 Volume 2>Chapter 2 - Wave Optics>Problems For Practice>Q 2

A thin film of thickness

4 \times 10^{- 5} cm

and

μ = 1.5

is illuminated by white light incident normal to its surface. What wavelength (expressed in

Å

) in the visible range be intensified in the reflected beam?

MEDIUM

12th CBSE

IMPORTANT

PHYSICS A Reference Book for Class 12 Volume 2>Chapter 2 - Wave Optics>Problems For Practice>Q 3

In a thin film, between two points

A

and

B

, eight fringes are observed with light of wavelength

5461 Å

. How many fringes will be observed between the same two points

A

and

B

if the wavelength of light used is

6500 Å

MEDIUM

12th CBSE

IMPORTANT

PHYSICS A Reference Book for Class 12 Volume 2>Chapter 2 - Wave Optics>Problems For Practice>Q 4

With a thin air film between two points,

6

fringes appear when light of wavelength

5890 Å

is used. Calculate the difference in the thickness of the film (expressed in

μm

) between the two points.

MEDIUM

12th CBSE

IMPORTANT

PHYSICS A Reference Book for Class 12 Volume 2>Chapter 2 - Wave Optics>Problems For Practice>Q 5

White light is incident normally on a plane parallel thin film of

μ = 1.5

. Find the minimum thickness of the film in

nm

for which light of

λ = 4000 Å

is absent from the reflected light.

HARD

12th CBSE

IMPORTANT

PHYSICS A Reference Book for Class 12 Volume 2>Chapter 2 - Wave Optics>Problems For Practice>Q 6

A soap film of refractive index

4 / 3

and thickness

1.5 \times 10^{- 4} cm

is illuminated by white light incident at angle of

45 °

. The reflected light is examined by a spectroscope in which a dark band corresponding to the wavelength

5 \times 10^{- 5} cm

is found. Find the order of the interference band.

HARD

12th CBSE

IMPORTANT

PHYSICS A Reference Book for Class 12 Volume 2>Chapter 2 - Wave Optics>Problems For Practice>Q 7

White light is incident on a soap film of

μ = 4 / 3

at an angle of

30 ° .

On examining the transmitted light with a spectrometer, a dark band of wavelength

5.5 \times 10^{- 7} m

is found. Minimum thickness of the film is

1.11 \times 10^{- n} m

. Value of

n

MEDIUM

12th CBSE

IMPORTANT

PHYSICS A Reference Book for Class 12 Volume 2>Chapter 2 - Wave Optics>Problems For Practice>Q 1

Thickness of a plate which will produce a change in optical path equal to half the wavelength

λ

of the light passing through it normally is

\frac{λ}{2 (μ - n)}

. Value of

n

if refractive index of the plate is

μ

MEDIUM

12th CBSE

IMPORTANT

PHYSICS A Reference Book for Class 12 Volume 2>Chapter 2 - Wave Optics>Problems For Practice>Q 2

When a thin sheet of a transparent material of thickness

7.2 \times 10^{- 4} cm

is introduced in the path of one of the interfering beams, the central fringe shifts to a position occupied by the sixth bright fringe. If

λ = 6 \times 10^{- 5} cm,

find the refractive index of the sheet.

A soap film 5×10-5 cm thick is viewed at an angle of 35° to the normal. Find the wavelength of light in the visible spectrum which will be absent from reflected light (μ=1.33). Given wavelength range of the visible spectrum is 3900Å to 7800Å.

Important Questions on Wave Optics

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A soap film $5 \times 10^{- 5} cm$ thick is viewed at an angle of $35 °$ to the normal. Find the wavelength of light in the visible spectrum which will be absent from reflected light $(μ = 1.33) .$ Given wavelength range of the visible spectrum is $3900 Å$ to $7800 Å$ .