Afrog is 80 cm in front of a lens whose focal length is +50 cm. another lens of focal length +20 cm, is 100 cm behind the first lens. where is the image of the frog located? is it real or virtual?

image location is at 12.5 cm distance from another lens

and image is real

Explanation:

given data

distance q = 80 cm

focal distance f = 50 cm

focal length  f2 = 20 cm

distance  = 100 cm

to find out

image of the frog located and  Is it real or virtual

solution

we apply here lens formula that is

1/f = 1/p + 1/ q

1/50 = 1/p + 1/80

p = 133.3 cm

so at another lens distance is  100 - 133.3

distance q = -33.3 cm

so lens formula

1/f = 1/p + 1/q

1/20 = -1/33.3 + 1/p

p = 12.5 cm

so image location is at 12.5 cm distance from another lens

and image is real