# Derive the lens formula two lenses of power 10 d and -5 d. calculate the power of new lens.

2
Log in to add a comment

Log in to add a comment

=>power of lens=5d

1/v+1/u=1/f

where v is the image distance,u is the object distance and f is the focal length of the lens.

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.

If the two lenses are combined - placed just after another at the geometric centers.

1/f = 1/f1 + 1/f2

P = P1 + P2 = 10 - 5 = 5 Dioptres

f = 1/P = 0.20 meter = 20 cm

1/f = 1/f1 + 1/f2

P = P1 + P2 = 10 - 5 = 5 Dioptres

f = 1/P = 0.20 meter = 20 cm