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Fill in the following blanks with suitable words:
(a) Most of the refraction of light rays entering the eye occurs at the outer surface of the _______
(b) The part of eye sensitive to light is_______
(c) The part of eye which alters the size of the pupil is_______
(d) When light is dim, the pupil becomes_______
(e) The iris controls the amount of_______entering the eye.
(f) The ciliary muscles control the shape of the _______
(g) To bring light from a distant object to a focus on the retina of the eye, the convex eye-lens needs to be made_______
(h) To bring light from a near object to a focus on the retina of the eye, the convex eye-lens needs to be made_______
The descriptions of five kinds of images are given below:
(a) diminished and virtual (b) enlarged and real
(c) enlarged and erect (d) real and inverted
(e) virtual and the same size
Which one of these describes the image formed:
(i) on the retina of the eye?
(ii) by a magnifying glass?
(iii) by a convex driving mirror on a car?
(iv) by a plane mirror?
(v) on the screen of a slide projector?
Fill in the blanks with suitable words:
(a) When a ray of light enters a prism, it bends.................the normal; as it leaves the prism, it bends ............ the normal.
(b) White light is composed of .............colours. The colour of white light deviated through the largest angle by a prism is..............
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.
(a) State the colour seen (i) at X, and (ii) at Y.
(b) Why do different colours of white light bend through different angles with respect to the incident beam of light?
A student claims that because of atmospheric refraction, the sun can be seen after it has set, and the day is, therefore, longer than if the earth had no atmosphere.
(a) What does the student mean by saying that the sun can be seen after it has set?
(b) Do you think that the students' conclusion is correct?
In an experiment to study the scattering of light by passing a beam of white light through a colloidal solution of sulphur in a transparent glass tank :
(a) Which colour is observed from the front of the glass tank? Does this colour correspond to the colour of sky on a clear day or the colour of sky around the sun at sunset ?
(b) Which colour is observed from the sides of the glass tank? Does this colour correspond to the colour of sky on a clear day or the colour of sky around the sun at sunset ?