Question

The power of concave lens of focal length 25 CM is......

Answer 1

Answer:

power =1/f ( m)

=1/ 0.25 [ since cm is converted into m ]

=100/25

= 4 dioptre

Answer 2

25 CM =0.25M

SO,

P=1/F

1/0.25

100/25

SO THE POWER IS -4D AS THE FOCAL LENGTH OF CONCAVE IS ALWAYS MINUS.