Two thin converging lenses of focal lengths 15cm and 30cm are held in contact. Calculate the power and focal length in combination. Share with your friends Share 2 Sanjay Upadhyay answered this Dear studentgiven f1=15cm and f2=30cmNow combined focal length will be1f=1f1+1f2or 1f=115+130=2+130=110or f=10cm now power is reciprocal of the focal length P=1f=10010=10D (100 is taken because the focal length is in cm)Regards 7 View Full Answer Aditi Salvi answered this Power of a combination of lenses is the sum of both their powers. That is, 100/15+100/30=300/30=10D Hence power of this combination is 10 D Focal length= 100/power =100/10=10cm Hence the focal length of the combination is 10cm. 2 Vishanth answered this Thank you 2
