A convex mirror has a radius of curvature whose magnitude is 47 cm. The mirror i
ID: 1604794 • Letter: A
Question
A convex mirror has a radius of curvature whose magnitude is 47 cm. The mirror is positioned on a horizontal optical bench with its front surface at 0 cm. A 12.0 cm long fluorescent lamp oriented vertically is placed at +97 cm. What is the focal length of the mirror?
At what distance from the mirror can we find a sharp image of the lamp?
How tall is the image of the lamp?
If the convex mirror were replaced by a plane mirror and the lamp moved to 188 cm from the plane mirror, how tall would the image be?
Explanation / Answer
focal length of the convex mirror is (f) =-R/2 = -23.5cm
mirror equation
1/di+1/do =1/f
1/97 + 1/di =1/(-23.5)
di = - 18.92 cm
m =hi/ho =-di/do
hi =(-di/do)*ho
=(-18.92/97)*12 cm
=2.34 cm
image be gives the same object height = 12 cm.