Advertisements
Advertisements
प्रश्न
Answer in brief:
The distance between two consecutive bright fringes in a biprism experiment using the light of wavelength 6000 Å is 0.32 mm by how much will the distance change if light of wavelength 4800 Å is used?
The distance between two bright fringes in a biprism experiment using light of wavelength 6000 A.U. 0.32 mm. By how much will the distance change, if the light of wavelength 4800 A.U. is used?
Advertisements
उत्तर १
Data: λ1 = 6000 Å = 6 × 10-7 m, λ2 = 4800 Å = 4.8 × 10-7 m, W1 = 0.32 mm = 3.2 × 10-4 m
Distance between consecutive bright fringes,
W = `(lambda "D")/"d"`
For `lambda_1, "W"_1 = (lambda_1"D")/"d"` and ...(1)
For `lambda_2, "W"_2 = (lambda_2"D")/"d"` and ...(2)
`"W"_2/"W"_1 = (lambda_2 "D"//"d")/(lambda_1 "D"//"d") = lambda_2/lambda_1`
`therefore "W"_2 = (lambda_2/lambda_1)"W"_1 = ((4.8 xx 10^-7)/(6 xx 10^-7)) (3.2 xx 10^-4)`
`= (0.8)(3.2 xx 10^-4)`m
`= 2.56 xx 10^-4` m
`therefore triangle "W" = "W"_1 - "W"_2`
= 3.2 × 10-4 m - 2.56 × 10-4 m
= 0.64 × 10-4 m
= 6.4 × 10-5 m
= 0.064 mm
उत्तर २
Given:
Distance between consecutive bright fringes,
yA = 0.32 mm = 0.32 × 10-3 m
λA = 6000 A.U. = 6 × 10-7 m, λB = 4800 A.U. = 4.8 × 10-7 m
Let yB be the distance between consecutive bright fringes when wavelength λB is used
To find: Change in distance between the fringes |yA – yB| Formula: yAλB = yBλA
Calculation:
From formula,
∴ yB = `("y"_"A""y"_"B")/(λ_"A") = (0.32 xx 10^-3 xx 4.8 xx 10^-7)/(6 xx 10^-7)`
= 0.256 × 10-3
∴ Change = |yA – yB|
= = |0.320 × 10-3 - 0.256 × 10-3|
= 0.064 × 10-3 m
= 0.064 mm
The change in distance between the fringes is 0.064 mm.
संबंधित प्रश्न
Define a wavefront.
Is the colour of 620 nm light and 780 nm light same? Is the colour of 620 nm light and 621 nm light same? How many colours are there in white light?
The wavelength of light in a medium is \[\lambda = \lambda_0 /\mu,\] where \[\lambda \] is the wavelength in vacuum. A beam of red light \[\left( \lambda_0 = 720\text{ nm} \right)\] enters water. The wavelength in water is \[\lambda = \lambda_0 /\mu = 540\text{ nm.}\] To a person under water, does this light appear green?
If we put a cardboard (say 20 cm × 20 cm) between a light source and our eyes, we can't see the light. But when we put the same cardboard between a sound source and out ear, we hear the sound almost clearly. Explain.
Is it necessary to have two waves of equal intensity to study interference pattern? Will there be an effect on clarity if the waves have unequal intensity?
An amplitude modulated (AM) radio wave bends appreciably round the corners of a 1 m × 1 m board but a frequency modulated (FM) wave only bends negligibly. If the average wavelengths of the AM and FM waves are \[\lambda_a and \lambda_f,\]
A light wave can travel
(a) in vacuum
(b) in vacuum only
(c) in a material medium
(d) in a material medium only
Which of the following properties of light conclusively support the wave theory of light?
(a) Light obeys the laws of reflection.
(b) Speed of light in water is smaller than its speed in vacuum.
(c) Light shows interference.
(d) Light shows photoelectric effect.
When light propagates in vacuum, there is an electric field as well as a magnetic field. These fields ____________ .
(a) are constant in time
(b) have zero average value
(c) are perpendicular to the direction of propagation of light.
(d) are mutually perpendicular
Three observers A, B and C measure the speed of light coming from a source to be νA, νBand νC. A moves towards the source and C moves away from the source at the same speed. B remains stationary. The surrounding space is water everywhere.
(a) \[\nu_A > \nu_B > \nu_C\]
(b) \[\nu_A < \nu_B < \nu_C\]
(c) \[\nu_A = \nu_B = \nu_C\]
(d) \[\nu_B = \frac{1}{2}\left( \nu_A + \nu_C \right)\]
The speed of yellow light in a certain liquid is 2.4 × 108 m s−1. Find the refractive index of the liquid.
Two narrow slits emitting light in phase are separated by a distance of 1⋅0 cm. The wavelength of the light is \[5 \cdot 0 \times {10}^{- 7} m.\] The interference pattern is observed on a screen placed at a distance of 1.0 m. (a) Find the separation between consecutive maxima. Can you expect to distinguish between these maxima? (b) Find the separation between the sources which will give a separation of 1.0 mm between consecutive maxima.
A parallel beam of light of wavelength 560 nm falls on a thin film of oil (refractive index = 1.4). What should be the minimum thickness of the film so that it strongly reflects the light?
A parallel beam of white light is incident normally on a water film 1.0 × 10−4 cm thick. Find the wavelengths in the visible range (400 nm − 700 nm) which are strongly transmitted by the film. Refractive index of water = 1.33.
A glass surface is coated by an oil film of uniform thickness 1.00 × 10−4 cm. The index of refraction of the oil is 1.25 and that of the glass is 1.50. Find the wavelengths of light in the visible region (400 nm − 750 nm) which are completely transmitted by the oil film under normal incidence.
Answer in brief:
In a double-slit arrangement, the slits are separated by a distance equal to 100 times the wavelength of the light passing through the slits.
- What is the angular separation in radians between the central maximum and an adjacent maximum?
- What is the distance between these maxima on a screen 50.0 cm from the slits?
White light consists of wavelengths from 400 nm to 700 nm. What will be the wavelength range seen when white light is passed through a glass of refractive index 1.55?
When light travels from an optically rarer medium to an optically denser medium, the speed decreases because of change in ______
Light follows wave nature because ______
The path difference between two waves meeting at a point is (11/4)λ. The phase difference between the two waves is ______
Which of the following cannot produce two coherent sources?
State any four conditions for obtaining well defined and steady interference patterns.
Two vectors of the same magnitude have a resultant equal to either of the two vectors. The angle between two vectors is
Light behaves as _________.
Light emerges out of a convex lens when a source of light kept at its focus. The shape of wavefront of the light is ______.
