Advertisements
Advertisements
प्रश्न
Solve Numerical example.
From the given data set, determine angular dispersion by the prism and dispersive power of its material for extreme colours. nR = 1.62 nV = 1.66, δR = 3.1°
Advertisements
उत्तर
Given: nR = 1.62, nV = 1.66, δR = 3.1°
To find: i. Angular dispersion (δVR)
ii. Dispersive power (ωVR)
Formula: i. δ = A (n − 1)
ii. δVR = δV − δR
iii. ω = `(δ_"V"-δ_"R")/(((δ_"V"+δ_"R")/2))`
Calculation: From formula (i),
δR = A(nR − 1)
∴ A = `δ_"R"/(("n"_"R"-1))=3.1/((1.62-1))=3.1/0.62`
∴ δV = A(nV − 1) = 5 × (1.66 − 1) = 3.3°
From formula (ii),
δVR = 3.3 − 3.1 = 0.2°
From formula (iii),
ωVR = `(3.3-3.1)/(((3.3+3.1)/2))=0.2/6.4xx2=0.2/3.2=1/16`
= 0.0625
- Angular dispersion by prism is 0.2°
- Dispersive power of material of prism is 0.0625.
APPEARS IN
संबंधित प्रश्न
A ray of light travels from water to air as shown in the diagram given below :
1) Copy the diagram and complete the path of the way. Given the critical angle for water is 48°.
2) State the condition so that internal reflection occurs in the above diagram.
Which colour of light has a higher critical angle? Red light or green light.
A light ray does not bend at the boundary in passing from one medium to the other medium if the angle of incident is ______.
Total internal reflection occurs only when a ray of light passes from a ______ medium to a ______ medium.
Calculate the speed of light in a medium whose critical angle is 30° ?
Swarali has got the following observations while doing an experiment. Answer her questions with the help of observations.
Swarali observed that the light bent away from the normal, while travelling from dense medium to rarer medium. When Swarali increased the values of angle of incidence (i), the values of angle of refraction (r) went on increasing. But at a certain angle of incidence, the light rays returned into the dense medium.
So, Swarali has some questions. Answer them –
a) Name this certain value of ‘i ’. What is the value of ‘r’ at that time ?
b) Name this process of returning of light in dense medium. Explain the process.
Solve the previous problem if the paperweight is inverted at its place so that the spherical surface touches the paper.
Plot a graph between
Angle of incidence versus angle of reflection,
Plot a graph between
Angle of incidence versus angle of refraction.
State two advantages of using a right-angle prism as a reflector, rather than a plane mirror.
Draw a diagram, properly labelled, to illustrate the use of a total reflecting prism (a right-angled isosceles prism) to turn a ray of light through 180°. Name an instrument in which this device is used.
The diagram shows a point source P inside a water container. Three rays A, B, and C starting from P are shown up to the water surface. Show in the diagram the path of these rays after striking the water surface. The critical angle for the water-air pair is 48°.
Choose the correct option.
Select the WRONG statement.
Choose the correct option.
Angles of deviation for extreme colours are given for different prisms. Select the one having maximum dispersive power of its material.
Observe the given figure and write appropriate phenomenon of light in the box.
Which one of the following is NOT the correct formula for refractive index of glass w.r.t. air (aμg) (i = angle of incidence, r = angle of refraction)
For total internal reflection to take place, the angle of inddence i and the refractive index µ of the medium must satisfy the inequality ____________.
What are the conditions to achieve total internal reflection?
What is a mirage? How does it occur?
What is the phenomenon used in optical fiber? Explain.
A light is entering from one medium refractive index `("RI" =5/3)` to another medium at an angle 30°. The angle of refraction for other medium is sin-1 `(5/6)`. then the increase in angle of incidence is ______ such that the ray of light reflected back into the same medium.
A ray of light passes from vacuum into a medium of refractive index µ, the angle of incidence is found to be twice the angle of refraction. Then the angle of incidence is ______.
- Assertion (A): Propagation of light through an optical fibre is due to total internal reflection taking place at the core-cladding interface.
- Reason (R): Refractive index of the material of the cladding of the optical fibre is greater than that of the core.
Name any two phenomena which take place in the formation of a rainbow.
State two differences between normal reflection and total internal reflection.
