Consider a spherical mirror and lens separated by 45 cm. The mirror is on the le
ID: 1455920 • Letter: C
Question
Consider a spherical mirror and lens separated by 45 cm. The mirror is on the left with a focal length of 100 cm. The lens is on the right with a focal length of 20 cm. A 5 cm tall object is placed 20 cm to the left of the lens.
a) If you only consider the rays that move to the right from the object, fully characterize the final image in the system. In other words provide final image location, real/virtual, upright/inverted, final magnification, and final image height.
b) If you only consider the rays that move to the left from the object, fully characterize the final image in the system. In other words provide final image location, real/virtual, upright/inverted, final magnification, and final image height.
Explanation / Answer
a) 1/v + 1/u = 1/f
=> 1/v = -1/20 + 1/20
=> v = infinity
=> Vfinal = 100 cm from spherical mirror -----------------> final image location
=> image is real
=> magnification = 0
=> final image height = 0 cm
b) Here, 1/v = 1/100 - 1/25
=> v = - 33.33 cm
=> 1/Vfinal = -1/20 + 1/78.33
=> Vfinal = - 26.85 cm from lens -----------------> final image location
=> image is real .
=> image is inverted .
=> magnification = - (33.33/25) * (26.85/78.33) = - 0.457
=> Final image height = 5 * 0.457 = 2.285 cm