When a person sees near objects clearly but distant objects appear blurred , then he has
Long sightedness
Short sightedness
Night blindness
Cataract
When sunlight falls on a triangular glass prism
A spectrum is obtained
Dispersion takes place
The prism separates the white light into many colours
All are true
The reciprocal of focal length is called the
Principal focus of the lens
Power of the lens
Magnification of the image
Length of the object
Which prisms replace mirrors in good periscope?
Totally reflecting prism
Diffuse reflecting prism
Regular reflecting prism
Triangular glass prism
Long sightedness can be corrected by using a
Diverging spectacle lens
Converging spectacle lens
Concave mirror
Convex mirror
The angle of incidence at which the angle of refraction is 900 is called
Total internal reflection
critical angle
Angle of reflection
Angle of incidence
The image which cannot be formed on a screen called
Virtual image
Real image
Laterally invited image
Diminished image
The image which can be produced on a screen is called
Laterally invented image
The average adult can focus object comfortably from about
25 cm to 1 m
25 cm to infinity
25 cm to 5 m
5 cm to infinity
The perpendicular to the mirror at the point where the incident ray strikes is called
Reflected ray
Incident ray
Normal
Refracted ray
