Draw a ray diagram showing the dispersion through a prism when a narrow beam of white light is incident on one of its refracting surfaces. Also indicate the order of the colours of the spectrum obtained.
How will you use two identical prisms so that a narrow beam of white light incident on one prism emerges out of the second prism as white light? Draw the diagram.
A person needs a lens of power –4.5 D for correction of her vision.
(a) What kind of defect in vision is she suffering from?
(b) What is the focal length of the corrective lens?
(c) What is the nature of the corrective lens?
How are we able to see nearby and also the distant objects clearly?
A student sitting at the back of the classroom cannot read clearly the letters written on the blackboard. What advice will a doctor give to her? Draw ray diagram for the correction of this defect.
Draw ray diagrams each showing (i) myopic eye and (ii) hypermetropic eye.
Which of the following statement is correct?
(a) A person with myopia can see distant objects clearly
(b) A person with hypermetropia can see nearby objects clearly
(c) A person with myopia can see nearby objects clearly
(d) A person with hypermetropia cannot see distant objects clearly
The focal length of the eye lens increases when eye muscles
(a) are relaxed and lens becomes thinner
(b) contract and lens becomes thicker
(c) are relaxed and lens becomes thicker
(d) contract and lens becomes thinner
When light rays enter the eye, most of the refraction occurs at the
(a) crystalline lens
(b) outer surface of the cornea
(c) iris
(d) pupil