Question

A convex mirror has a focal
length of 0.9m. An object with a
height of 0.40 m Ps 2.5m
from the
mirror.
a) Calculate the image distance
b) Calulate the image height​

Answer 1

Answer:

Use the lens equation:

1/di + 1/do = 1/f

where do = 40.0 cm and f = 30.0 cm. Solve for di.

1/di = 1/f - 1/do =1/(30.0 cm) - 1/(40.0 cm) = 0.00833 /cm

di = 1/(0.00833 /cm) = 120. cm

Then use the -di/do = hi/ho to find hi

It is now known that ho = 3.0 cm; do = 40.0 cm; di = 120. cm. Substitute and solve.

hi = -ho *(di/do) = -(3.0 cm) *(120. cm)/(40.0 cm) = -9.0 cm