Object is 2 F , the ray diagram is given below :
The nature of the images are :
- real,
- inverted
- equal size with respect to object.
We havce, m = v/ u
= 8/8
= 1
For power of lens
here focal length f = 4 cm
= 4/100 m
= 0.04 m = 25 D
Power of lens =25 D