Question

A convex lens of f 40cm and concave lens of f 50 cm are placed in contact with each other find focal lengh of combination

Answer 1

Focal length of combination= f1 + f2

f1= +40 cm (convex)

f2= -50 cm (concave)

f = f1+f2

f = 40-50

f = - 10

Hence final length of combination is -10cm

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