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
A diverging lens has
A real principal focus
A virtual principal focus
No principal focus
A principal focus same as a converging lens
The centre of the lens is its
Principal axis
Principal focus
Optic centre
Focal length
At which condition total internal reflection takes place?
Angle of incidence > critical angle
Angle of incidence = critical angle
Angle of incidence < critical angle
Angle of incidence = Angle of reflection .
When a ray of light enters an optically denser medium it
Bend towards the normal
Bend away from the normal
Pass parallel to the normal
Never bends
The image which cannot be formed on a screen called
Virtual image
Real image
Laterally invited image
Diminished image
Long sightedness can be corrected by using a
Diverging spectacle lens
Converging spectacle lens
Concave mirror
Convex mirror
Which act as the reflecting surface in an ordinary mirror?
Glass
Mirror
Silver at the back of the glass
All the above
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 image which can be produced on a screen is called
Laterally invented image
