UNIT.2.OPTICS 2MARKS REVIEW


1.       Differentiate luminous and non luminous objects.
2.       State the properties of light.
3.       What is meant by refraction?
4.       State the first law of refraction oflight.
5.       State the second law of refraction (or)state Snell’s law.
6.       Define dispersion of light.
7.       What is VIBGYOR?What are the colours present in if?
8.       What is meant by scattering?
9.       What is elastic scattering?
10.   What is inelastic scattering?
11.   What is Rayleigh scattering?
12.   State Rayleigh scattering law.
13.   Why sky appears blue at noon?
14.   Why sun appears red at sunset or sunrise?
15.   Write note on Mie scattering
16.   Why does clouds appear white?
17.   What is Tyndall scattering?
18.   State Raman law of scattering of light.
19.   What is Rayleigh line?
20.   What are Raman lines?
21.   What are Stokes and Antistokes lines?
22.   What is a lens?state types.
23.   What iare the applications of convex lenses?
24.   What are the applications of concave lenses?
25.   What is lens formula?
26.   Write note of sign convention.
27.   Define magnification of lens.
28.   What is lens maker's formula?what is its significance?
29.   What is power of a lens?Write formula and unit.
30.   Differentiate convex and concave lenses.
31.   State various parts of eye and their functions.
32.   Draw the diagram of eye and label the parts.
33.   What is meant by power of accomodation of eye?
34.   Define:Least diatance of distinct vision.
35.   Name the various defects of eye.
36.   What is myopia?state the reason,correcting method for myopia.
37.   What is Hypermetropia?state the reason,correcting method for hypermetropia.
38.   What is presbyopia?state the reason,correcting method for presbyopia.
39.   What is astigmatism?state the reason,correcting method for astigmatism.
40.   What are the uses of simple microscope?
41.   What are the advantages of Telescopes?
42.   What are the disadvantages of Telescopes?
43.    
Luminous  objects
Sun,Stars
Non luminous objects
Moon,
Speed of light in vacuum
3 × 108 ms–1
Second law of refraction
Snell’s law
Snell’s law
sin i /sin r  = µ2/ µ1
Rayleigh scattering law
‘S’ 1/ λ4
Mie scattering explains
white appearance of the clouds
Rayleigh’s scattering law  explains
1.Sky blue colour
2.Sun appears red
Tyndall Scattering
Scattering in colloidal solutions
Lens maker’s formula
Power of a lens
Unit of Power of a lens
Dioptre
Power of a convex len
Positive

power of a concave lens
Negative
Convex Lens
thicker in the middle than
at edges
Convex Lens
converging lens.
Convex Lens
produces mostly real images
Convex Lens
used to treat hypermeteropia
Concave Lens
thinner in the middle than
at edges.
Concave Lens
diverging lens
Concave Lens
produces virtual images
Concave Lens
used to treat myopia.
Iris
controls amount of light entering
Pupil
pathway for the light to retina
Retina
on which real and inverted image of objects is formed
Ciliary muscles
helps to change the focal
length of the eye lens
Eye Lens
convex in nature.
Persistence of vision
less than 0.1 second
Near point of eye.
25 cm
far point of the eye.
Infinity
Myopia
short sightedness
Due to lengthening of eye ball
focal length of eye lens is reduced
image of distant objects are formed before the retina
corrected using a concave lens
Hypermeteropia
Long sightedness,
due to the shortening of
eye ball
focal length of eye lens is
increased
image of nearby objects are formed behind the retina
corrected using a convex lens
Presbyopia
‘old age hypermetropia’
eye loses its power of accommodation
iliary muscles become
weak and the eye-lens become rigid (infl exible)
corrected by ‘bifocal lenses’.
Astigmatism
eye cannot see parallel and
horizontal lines clearly
imperfect structure of
eye lens
Due to development of cataract
on the lens, ulceration of cornea, injury to the
refracting surfaces,
corrected by using cylindrical lenses (Torrid  lenses)
Uses of Simple microscope
watch repairers and jewellers
read small letters clearly
observe parts of flower, insects etc
bserve finger prints in the field of forensic science