PHYS 2426 – Engineering Physics II
Image Formation by Mirrors and Ray Diagrams
Leader: ___________________
Skeptic: ___________________
Recorder: __________________________
Encourager: ________________________
Materials
Convex/Concave Mirror
Ruler
Procedure
Place the mirror with the concave side facing you that you can see your “reflection”. More
correctly, what you are observing is the image formed by the mirror.
Q1) Describe your image in terms of size and orientation. (I.e. larger than actual size, smaller
than actual size, actual size, right-side up or upside down)
Move towards the mirror while observing your image.
Q2) Describe how the image changes as you bring the mirror towards you.
Hold the mirror quite close to your face.
Q3) Describe what happens to your image when the mirror is quite close to your face.
Hold the mirror with the convex side facing you at arm’s length.
Q4) Describe your image in terms of size and orientation.
Move the mirror towards you while observing your image.
Q5) Describe how the image changes as you bring the mirror towards you.
Q6) Describe the image in the convex mirror when it is quite close to your face. How is this
different than what you observed in the concave mirror?
We will draw three ray diagrams to describe the images.
Q7) The figure above shows an object in front of a concave mirror. If you draw a ray from the
tip of the object through the focal point, F, how will it reflect? Use a straight edge and draw the
ray.
Q8) If you draw a ray from the tip of the object parallel to the axis how will it reflect? Draw the
ray.
Q9) Do the rays reflected from the mirror converge to a point or diverge?
Q10) Is the image located in front or behind the mirror? It is customary to show the image by
drawing an arrow from the axis to the point to which the rays converge. Show the location of the
image on the diagram.
Q11) To check your work, look at a third ray. If you draw a ray from the tip of the object
through the center of the circle, C, how will it reflect? Draw the ray.
A real image is formed by converging rays and a virtual image is formed by diverging rays.
Q12) Is the image you’ve found real or virtual? Explain.
Q13) Is the image upright or inverted?
The magnification is defined as M = hi/ho where hi is the height of the image and ho is the height
of the object. The magnification is negative when the object is inverted and it is positive when
the image is upright.
Q14) Measure the height of the object and of the image and determine the magnification.
Q15) To which situation when you observed your image in the mirror does this ray diagram
correspond?
Q16) The figure above shows an object in front of a concave mirror but this time the object is
located between the focal point and the mirror.. If you draw a ray from the focal point, F,
through the tip of the object to mirror, how will it reflect? Draw the ray.
Q17) If you draw a ray from the tip of the object parallel to the axis how will it reflect? Draw
the ray.
Q18) Do the rays reflected from the mirror converge to a point or diverge?
When the rays diverge in front of the mirror, we can find the image by backtracking the
diverging rays.
Q19) Is the image located in front or behind the mirror? Show the location of the image on the
diagram.
Q20) To check your work, look at a third ray. If you draw a ray from the center through the tip
of the object, C, how will it reflect? Draw the ray.
Q21) Is the image you’ve found real or virtual? Explain.
Q22) Is the image upright or inverted?
Q23) Measure the height of the object and of the image and determine the magnification.
Q24) To which situation when you observed your image in the mirror does this ray diagram
correspond?
Q25) The figure above shows an object in front of a convex mirror. If you draw a ray from the
tip of the object parallel to the axis, how will it reflect? Draw the ray.
Q26) If you draw a ray from the tip of the object aimed towards the focal point, how will it
reflect? Draw the ray.
Q27) Do the rays reflected from the mirror converge to a point or diverge?
Q28) Is the image located in front or behind the mirror? Show the location of the image on the
diagram.
Q29) To check your work, look at a third ray. If you draw a ray from the tip of the object aimed
at the center of the circle, C, how will it reflect? Draw the ray.
Q30) Is the image you’ve found real or virtual? Explain.
Q31) Is the image upright or inverted?
Q32) Measure the height of the object and of the image and determine the magnification.
Q33) To which situation when you observed your image in the mirror does this correspond?