What type of lens will form when a tumbler is filled with water?
Bi convex
Concavoconvex
Plano convex
Biconcave
Light enters from air into a glass plate having refractive index 1.50. What is the speed of light in glass ?(The speed of light in vacuum is 3 x 108 m/s)
2 x 108 m/s
1.82 x 108 m/s
4 x 108 m/s
2 x 106 m/s
SI unit of power of lens is
metre
horse power
dioptre
watt
The ratio of the sine of the angle of incidence to the sine of angle of refraction is constant and is called
Malu's law
Snell's law
Optical density
Relative density
A virtual image is one which
can be taken on a screen
cannot be taken on a screen
sometimes can be and sometimes cannot be taken on a screen
is formed only by a concave mirror
A man is using concave mirror for shaving.If his face is 20 cm from the mirror having magnification 2,what will be the radius of curvature of the mirror?
60 cm
80 cm
50 cm
40 cm
A concave mirror cannot be used as :
a magnifying mirror
a torch reflector
a dentist's mirror
a rear view mirror
What is called reciprocal of focal length of a lens ?
Power
Radius
Centre of curvature
Focus
The mirror used by a dentist to examine the teeth of a patient is :
convex
concave
plane
both concave and convex
The sum of the reciprocals of object distance and image distance is equal to the
focal length of a mirror
reciprocal of the focal length
radius of curvature
magnification
