Advertisements
Advertisements
प्रश्न
What will happen if another similar glass prism is placed upside down behind the first prism?
Advertisements
उत्तर
If a second, similar glass prism is placed upside down behind the first prism, recombination of seven colours takes place and a patch of ordinary white light is obtained on a screen placed behind the second prism. The recombination of colours took place because the second prism was placed upside down, because of which the refraction produced by the second prism was equal and opposite to the refraction produced by the first prism.
APPEARS IN
संबंधित प्रश्न
A narrow beam PQ of white light is passing through a glass prism ABC as shown in the diagram.

Trace it on your answer sheet and show the path of the emergent beam as observed on the screen DE.
(i) Write the name and cause of the phenomenon observed.
(ii) Where else in nature is this phenomenon observed?
(iii) Based on this observation, state the conclusion which can be drawn about the constituents of white light.
In the following diagram the correctly marked angles are :

(a) ∠A and ∠e
(b) ∠i, ∠A and ∠D
(c) ∠A ∠r and ∠e
(b) ∠A ∠r and ∠D
State the cause of dispersion of white light
In the figure given alongside, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a spectrum YX on the screen.
State the colour seen (i) at X, and (ii) at Y.
What are the seven colours seen in a rainbow?
The colour of white light which is deviated the maximum on passing through the glass prism is:
(a) blue
(b) indigo
(c) red
(d) orange
When white light passes through a prism, it ............
The speed of light in air or vacuum is
The frequency range of visible light is from 3.75 × 1014 Hz to 7.5 × 1014 Hz. Calculate its wavelength range. Take speed of light = 3 × 108 m/s.
A wave has wavelength 50Å of State its one use.
A student has to trace the path of a ray of light through a glass prism. List four precautions he should observe for better results.
What do you understand by spectrum? Name the seven prominent colours in order, as obtained in the spectrum of white light.
In the figure, a beam of light consisting of three colours blue, red, and yellow is incident on a prism and on a rectangular glass block respectively. Complete the diagram by drawings of the refracted and emergent rays.

The periscope is an optical device with a polished surface that reflects the light falling on it.
Assertion: We can see the rainbow in the sky when the rain starts falling after a spell of bright sunlight.
Reason: The rainbow is formed due to the dispersion of light.
During dispersion of white light by prism placed in air, for a particular value of angle of prism,
The dispersive powers of flint glass and crown glass are 0.053 and 0.034, respectively and their mean refractive indices are 1.68 and 1.53 for white light. Calculate the angle of the flint glass prism required to form an achromatic combination with a crown glass prism of refracting angle 4°:
A prism of refractive index `sqrt2` and refracting angle A produces minimum deviation δm of a ray on one face at an angle of incidence 45°, The values of A and δm are, respectively ______.
State True or False:
"Wavelength of red light is close to 700 nm.”
Observe the given diagram and answer the questions:

- Name the process shown in the figure.
- Name the colour that deviates the most.
- Name the colour that deviates the least.
- Name any one phenomenon in nature which is based on the above process.
- Define ‘spectrum’.
