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Question
Write three conditions necessary to obtain a pure spectrum on a screen. Name the instrument in which the conditions stated by you are fulfilled.
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Solution
The three conditions necessary to obtain a pure spectrum on a screen are:
(i) A narrow parallel beam of light should be made incident on the prism.
(ii) The prism should be placed in the position of minimum deviation.
(iii) The emergent parallel beam should be focussed on the screen.
These conditions are fulfilled in the spectrometer.
RELATED QUESTIONS
A student traces the path of a ray of light through a triangular glass prism for different values of angle of incidence. On analyzing the ray diagrams, which one of the following conclusions is he likely to draw?
(A) The emergent ray is parallel to the incident ray.
(B) The emergent ray bends at an angle to the direction of the incident ray.
(C) The emergent ray and the refracted ray are at right angles to each other.
(D) The emergent ray is perpendicular to the incident ray.
The colour of white light which suffers the maximum bending (or maximum refraction) on passing through a glass prism is:
(a) yellow
(b) orange
(c) red
(d) violet
When a white light ray falls on a prism, the ray at its first surface suffers ______.
In an experiment to trace the path of a ray of light through a triangular glass prism, a student would observe that the emergent ray
(a) is parallel to the incident ray.
(b) is along the same direction of incident ray.
(c) gets deviated and bends towards the thinner part of the prism.
(d) gets deviated and bends towards the thicker part (base) of the prism.
If a monochromatic beam of light undergoes minimum deviation through an equiangular prism, how does the beam pass through the prism, with respect to its base?
The wavelength range of white light is ______.
What is the cause of the dispersion of white light through a glass prism? Draw a ray diagram to show the path of light when two identical glass prisms are arranged together in an inverted position with respect to each other and a narrow beam of white light is allowed to fall obliquely on one of the faces of the prisms.
What is Newton’s disc?
During dispersion of white light by prism placed in air, for a particular value of angle of prism,
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 ______.
