A thin convex lens of focal length 25 cm and aperture 10 cm is cut to have a hole of aperture 5 cm at the centre. The power of lens now will be:
1
2 D
2
4 D
3
1 D
4
8 D
A thin convex lens of focal length 25 cm and aperture 10 cm is cut to have a hole of aperture 5 cm at the centre. The power of lens now will be: