A beam of light incident on a convex lens parallel to its principal axis converges at a point on the principal axis. Name the point.
None of these
First focus
Optical centre
Second focus
Which is diverging lens?
All of these
Concavo convex lens
equi-convex lens
Equi concave lens
The power of a concave lens of focal length 20 cm is ____________
50 D
0.05
-5 D
5D
Which lens is converging?
Concave lens
convex lens
Both (a) and (b)
On reducing the focal length of a lens its power
Doesnot change
Nothing can ve said
Decreases
Increases
A ray of light directed towards the optical centre of a lens, after refraction:
is reflected black
Passes through the focus
Be comes paralll to the principal axis after refraction
Passes undeviated
A ray of light incident on a lens parallel to its principal axis, after refraction passes through.
The centre of curvature of its second surface
Its first focus
Its optical centre
its second focus
A ray of light incident at a point on the principal axis of a convex lens, passes un deviated through the lens. What special name is given to this point on the principal axis?
First focal point
Second focal point
A con cavo-convex lens is
Thick at the centre and thin at the periphery
Thin at the centre and thick at the periphery
Thick at the centre with one surface plane
Thin at the centre with one surface plane
A convexo - concave lens is
