Question

if the image formed by a lens for all positions of an object placed in front of it is always erect and diminished what is nature of this lens draw a ray diagram to justify your answer of the numerical values of power of this lens is 10 d what is focal length in Cartesian system

Answer 1

Answer.......

Power of a lens is given by the relation...

P = 1/f(in meter)

P=10D

F=1/p

=1/10

=0.1m

Or. -10cm,(as lens in concave lens. )

Hope it helps you

Answer 2

Answer:

the lens is concave and the focal length is 10 cm as it is the concave lens the focal length is -10

Explanation:

only concave lens forms a diminished and erect image when placed in front of the lens.                

                      we know that F=1/p

             so, power=10d which is already given in the question

                   f=1/10     in terms of meters

                   f=100/10 in terms of cm

                  therefore f=-10 cm

                             here f=-10 because concave lens have focal length negative