"LENS COMBINATIONS, THICK LENSES, GAUSSIAN FORMULA. Definitions of variables follow: FOCAL_L? = effective focal length of thick lens #?, ?=1 or 2 H?1, H?2 = locations of first and second principal planes of lens #?, ?=1 or 2 FFL1, BFL2 = front focal length of lens #1, back focal length of lens #2 H??_H? = distance from princ. plane of lens #? to system princ. plane. FOCAL_LENGTH = system focal length measured from system princ. planes S[I], S[O] = image and object distances of system M[T] = transverse magnitization of system D = distance from lens #1 second princ. plane to lens #2 first princ. plane D? = distances between princ. planes of each thick lens N[L?] = index of lense #?, N[M] = index of medium (air = 1) R?1, R?2 = radii of curvature of lens #?, ?=1 or 2 Note: distances to right are considered +. (c) Copyright PCSCC, Inc., 1993 *** Answer(s) to problem *** Note: variables are set to proper values at entry. the indiviual focal lengths are FOCAL_L1=FOCAL_L2= 34.48 mm. The system focal length is FOCAL_LENGTH=30.52mm Type any key to exit. || Two identical bi-convex lenses are separated by 30 mm. Each lens has a radius of 50 and 30 mm, a thickness of 20 mm and an index of 1.6. Calculate individual and system focal lengths. Type comma key to see answer. Type (F2) to return to application file."