Focal Length of lens A is +10cm & lens B is -5cm. Find combined power 

Asked by akshata.shukla1910 | 13th Aug, 2021, 12:43: PM

Expert Answer:

focal length of lens A  = + 10cm = +0.1 m
focal length of lens B = -5 cm = - 0.05 m 
 
Power of lens A = 1/ f (in metres) = 1/0.1 = + 10 D
Power of lens B = 1/ f = 1/(-0.05) = -20 D
 
Power of lens combined = + 10 + (- 20) = 10 -20 = - 10 D 

Answered by Shiwani Sawant | 13th Aug, 2021, 04:44: PM