Question

You place a 24-cm focal length convex lens at a distance of 50 cm in front of a concave lens with a focal length of -42 cm . Then you place a small lightbulb (2 cm tall) 29 cm in front of the convex lens. A)Determine the distance from the second lens to the final image

B)Determine the orientation of the final image. C)Is the final image real or virtual.

Answer 1

distance is 139.2 cm

image is inverted and virtual

and 79.36 cm in front of 2nd lens

Step-by-step explanation:

Given data

convex focal length = 24 cm

distance = 50 cm

concave focal length = -42 cm

light bulb height = 2 cm

distance = 29 cm

to find out

Determine the distance and orientation and image real or virtual

solution

we apply here lens formula for convex

1/f = 1/p + 1/q

here f = 24 and p = 29 so find q

1/24 = 1/29 + 1/q

q = 139.2 cm

so distance is 139.2 cm

and

lens formula for concave

f = - 42 and p = 50 - 139.2 = -89.2 cm so find q

1/f = 1/p + 1/q

- 1/42 = - 1/89.2 + 1/q

q = −79.36 cm

so image is inverted and virtual

and 79.36 cm in front of 2nd lens