The centre of the lens is its
Principal axis
Principal focus
Optic centre .
Focal length.
Which prism replace mirrors in good periscope?
Totally reflecting prism
Diffuse reflecting prism
Regular reflecting prism
Triangular glass prism
The bending of light when it passes from one medium to another is called
Reflection
Refraction
Total internal reflection
Diffuse reflection
Speed of light in a transparent solid is 2.10 x 108 m/s. Find its absolute refractive index?
1
2
1.43
2.43
the fatter ( more curved ) a converging lens is
The shorter its focal length and more it magnifies
The longer its focal length and more it magnifies
The longer its focal length and less it magnifies
The shorter its focal length and less it magnifies
If a parallel beam of light falls on a plane mirror or on a perfectly polished surface.
Regular reflection occurs
Diffuse reflection occurs
Total internal reflection occurs
Refraction occurs
The bending up of light when passing from one medium to another is known as
reflection
refraction
dispersion
none of these
When dispersion occurs due to fall of light in a prism we will get a colour pattern or a band of colours known as
white band
spectrum
ultraviolet rays
A diverging lens has
A real principal focus
A virtual principal focus
No principal focus
A principal focus same as a converging lens
A person watching a fish in a fish tank, its size thus seen will be
big
small
not comparable
