A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12cm from P. At what point does the beam converge if the lens is: a convex lens of focal length 20cm?

A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12cm from P. At what point does thebeam converge if the lens is: a concave lens of focal length 16cm?

A ocnverging bem of light forms of a sharp image on a screen. lens is placed in the path of the beam at 10 cm from the screen.It si found that screen has to be moved 8 cm further away from the lens to obtain a sharp image.Find the focal length and natrue of the lens.

A beam of light is converging towards a point on a screen.A plane parallel plate of glass is introduced in the path of this converging beam.How will the point of convergence be shited ?Draw the ray diagram.

If the focal length of a converging lens is 50 cm. What is the power of the Lens ?

A convex lens becomes less converging when placed in

A concave lens is kept in contact with convex lens of focal length 20 cm.The combination works as convex lens of focal length 50 cm. Find the power of concave lens.

A thin douel convex lens has surfaces of radii of curature 30 cm each.Find the refractive index of the material of lens,if the focal length is 25 cm.