Question

Shaving/makeup mirrors typically have one flat and one concave (magnifying) surface. You find that you can project a magnified image of a lightbulb onto the wall of your bathroom if you hold the mirror 2.0 m from the bulb and 3.5 m from the wall. What is the magnification of the image? What is the focal length of the mirror?

You have a semicircular disk of glass with an index of refraction of n = 1.57. Find the incident angle θ for which the beam of light in the figure will hit the indicated point on the screen.

Answer 1

1.) di is + , if the image is located on the object's side of the mirror.

f is + , if the mirror is a concave mirror

di = 3.5 m
do = 2.0 m
Magnification = - di/do = -3.5/2 = -1.75
Negative Sign indicates that the image is Inverted image (and therefore, also real)

Focal length:-

f = uv/( u + v) = 2*3.5 / (2+ 3.5) = 1.27 m

2.) Now, as figure is not given in the question, so I will tell the formula and an idea to do this question

​​​​​​

1* = 1.57* ;  = Perpendicular/ Base

By this , you can find the incident angle .