"Om Sai Ram"
Worksheet
of Light
1.
You are given kerosene, turpentine oil and water. In which of these does the
light ray
travel
fastest? Given refractive index of kerosene = 1. 44, Refractive index of
turpentine
1· 47, refractive index of water = 1· 33.
2.
Under what condition a convex lens when placed in a medium behaves as an
ordinary
glass
plate?
3.
Light having a free space wavelength λ= 500 nm passes from vacuum into diamond
having
refractive index 2.4. What would be the wavelength of light in the diamond?
4.
A ray of light is travelling in water medium falls on the water-air interface
at an angle
of
45° with the vertical. Will it be possible by the ray of light to come out of
the water
surface?
5. A virtual image cannot be focused on a
screen.” this statement appears to be
contradictory
as we focus a virtual image onto a screen, i. e retina explain it.
6. In what way is the word AMBULANCE
painted in front of the hospital vans? Why is it painted this way?
7. A concave mirror and convex lens are
held in water. What change, if any, do you
expect
to find in the focal length of either?
8.
‘ Vehicles in this mirror are closer than they appear’. This warning is printed
on the
convex
mirror outside the driver’s side of a vehicle. What is the reason for this
warning?
9.
A glass tumbler is placed over a coin and filled with water. Coin disappears
after
sometime
when seen from the sides of the tumbler. Give suitable name for the
phenomena
observed.
10.
If a lens has been blackened in strips, what will be the difference in the
nature of the
image?
11.
How many images are seen when two mirrors are placed in parallel?
12
. Is it possible for a lens to act as a convergent in one medium and divergent
in another?
13.
What happens to the image distance in the eye when we increase the distance of
an
object
from the eye?
14.
A student has difficulty in reading the black board while sitting in the last
row. What
would
be the defect the student is suffering from? How can it be corrected?
15.
A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What
should
be
the nature of the corrective lens used to restore proper vision?
16.
A person is able to see objects clearly only when these are lying at distances
Between
50 cm and 300 cm from his eye.
(a)
What kind of defects of vision is he suffering from?
(b)
What kind of lenses will be required to increase his range of vision from 25 cm
to
infinity? Explain briefly.
17. A beam of white light is passed
through a hollow prism, will it produce a spectrum?
18. Do all people looking at a star,
locate it at the same apparent position? If not explain.
19. When a torch light is focussed on the
eye which cells get activated immediately?
a) Sensory cells b) light sensitive cells
c) Cells of the ciliary muscles d) cells at the blind spot
20. The defect in vision developed due to gradual weakening of ciliary
muscle and diminishing
flexibility of eye lens is:
a) Myopia
b) hypermetropia c) night blindness d) presbyopia
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