Two slits in Young's experiment are 0 . 02 cm apart. The interference fringes for the light of wavelength 6000 A ∘ are formed on a screen 80 cm away. Calculate the distance of the fifth bright fringe.

Given, D = 80 cm = 80 × 10 - 2 m d = 0 . 02 cm = 0 . 02 × 10 - 2 m Now distance of fifth bright fringe = 5 y where y = fringe width = D λ d = 5 × D λ d = 5 × 80 × 10 - 2 × 6000 × 10 - 10 0 . 02 × 10 - 2 = 12 × 10 - 3 m = 12 mm = 1 . 2 cm This is the required answer.

In a two slits experiment with monochromatic light, fringes are obtained on a screen placed at some distance from the slits. If the screen is moved by 5 × 10 - 2 m towards the slits, the change in the fringe width is 3 × 10 - 5 m . If the distance between the slits is 10 - 3 m , calculate the wavelength of light used

The formula used β = λ D d where β is fringe width λ is the wavelength of light D is the distance between slit and screen. d is the distance between slits. Change in fringe width when screen distance from slits is changed by ∆ D is given by ⇒ ∆ β = λ ( ∆ D ) d ⇒ λ = d ( ∆ β ) ∆ D = ( 10 - 3 ) ( 3 × 10 - 5 ) 5 × 10 - 2 ⇒ λ = 6000 A o

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The intensity of light pulse travelling in an optical fibre decrease according to the relation

$I = I_{0} e^{- α x}$
The intensity of light is reduced to 20% of its initial value after a distance x equal to

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Important Questions on Wave Optics

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IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 31 - Wave Optics>BEGINNER'S BOX - 1>Q 1

Consider interference between two sources of intensities

I

and

4 I

. Obtain intensity at a point where the phase difference is

\frac{π}{2}

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Beta Question Bank for Medical: Physics>Chapter 31 - Wave Optics>BEGINNER'S BOX - 1>Q 2

Two coherent sources, whose intensity ratio is

16 : 1

produce interference fringes. If the ratio of intensity of maxima and minima in the fringe system is

\frac{25}{3 α}

. Find value of

α .

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Beta Question Bank for Medical: Physics>Chapter 31 - Wave Optics>BEGINNER'S BOX - 1>Q 3

Consider interference between two sources of intensity $I$ and $4 I$ . Find the resultant intensity. where the phase difference is

(a) $\frac{π}{4}$ (b) $π$ (c) $4 π$

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Beta Question Bank for Medical: Physics>Chapter 31 - Wave Optics>BEGINNER'S BOX - 2>Q 1

In Young's double-slit experiment, the slits are

2 mm

apart and are illuminated with a mixture of two-wavelength,

λ

= 7500 \overset{\circ}{A}

and

λ'

= 9000 \overset{\circ}{A}

. At what minimum distance from the common central bright fringe on a screen

2 m

from the slits will a bright fringe from one interference pattern coincide with a bright fringe from the other?

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Beta Question Bank for Medical: Physics>Chapter 31 - Wave Optics>BEGINNER'S BOX - 2>Q 2

In a Young's double slit experiment the angular width of fringe formed on a distant screen is

0.1

radian. Find the distance between the two slits if wavelength of light used is

6000 A^{o}

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Beta Question Bank for Medical: Physics>Chapter 31 - Wave Optics>BEGINNER'S BOX - 2>Q 3

Two slits in Young's experiment are

0.02 cm

apart. The interference fringes for the light of wavelength

6000 \overset{\circ}{A}

are formed on a screen

80 cm

away. Calculate the distance of the fifth bright fringe.

EASY

NEET

IMPORTANT

Beta Question Bank for Medical: Physics>Chapter 31 - Wave Optics>BEGINNER'S BOX - 2>Q 4

In Young's double-slit experiment, two slits are separated by

3 m m

distance and illuminated by light of wavelength

480 n m

. The screen is at

2 m

from the plane of the slits. Calculate the separation between the

8^{t h}

bright fringe and the

3^{r d}

dark fringe observed with respect to the central bright fringe.

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Beta Question Bank for Medical: Physics>Chapter 31 - Wave Optics>BEGINNER'S BOX - 2>Q 5

In a two slits experiment with monochromatic light, fringes are obtained on a screen placed at some distance from the slits. If the screen is moved by

5 \times 10^{- 2} m

towards the slits, the change in the fringe width is

3 \times 10^{- 5} m

. If the distance between the slits is

10^{- 3} m

, calculate the wavelength of light used

The intensity of light pulse travelling in an optical fibre decrease according to the relation I=I0e-αx The intensity of light is reduced to 20% of its initial value after a distance x equal to

Important Questions on Wave Optics

Learn and Prepare for any exam you want !

The intensity of light pulse travelling in an optical fibre decrease according to the relation

$I = I_{0} e^{- α x}$
The intensity of light is reduced to 20% of its initial value after a distance x equal to