Sec7 Curved Mirrors Physics to Go
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ℎ𝑜
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𝑀𝑖𝑟𝑟𝑜𝑟 𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛:
1
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1) A concave mirror has a radius of curvature of 10 cm. For each of the
following cases sketch a ray diagram and locate the image. Measure the
images height and distance from the mirror; then calculate its magnification
with both equations above. Next, calculate the image distance from the
mirror using the mirror equation. Finally, describe which case number and
case title the problem represents from your notes (exp: case 3 between
center of curvature and focal point). All diagrams should be drawn to scale.
a. An upright pencil of height 3 cm placed 14 cm from the mirror.
b. An upright pencil of height 2 cm placed 10 cm from the mirror.
c. An upright pencil of height 4 cm placed 5 cm from the mirror.
2) Another concave mirror has a radius of curvature of 6 cm. For each of the
following cases sketch a ray diagram and locate the image. Measure the
images height and distance from the mirror; then calculate its magnification
with both equations above. Next, calculate the image distance from the
mirror using the mirror equation. Finally, describe which case number and
case title the problem represents from your notes. All diagrams should be
drawn to scale.
a. An upright pencil of height 2 cm placed 2 cm from the mirror.
b. An upright pencil of height 4 cm placed 5 cm from the mirror.
3) A convex mirror has a radius of curvature of 8 cm. For each of the following
cases sketch a ray diagram and locate the image. Measure the images height
and distance from the mirror; then calculate its magnification with both
equations above. All diagrams should be drawn to scale.
a. An upright pencil of height 3 cm placed 11 cm from the mirror.
b. An upright pencil of height 3 cm placed 5 cm from the mirror.
4) If an object is placed outside the focal length of a concave mirror, what type
of image will be formed (real or virtual, upright or inverted)? Will the image
appear to be in front of or behind the mirror?
5) Can you use a convex or concave mirror to burn a hole in paper by focusing
light at the mirrors focal point? Which mirror works and which does not?
Explain why one mirror can but the other cannot.
6) What test could you perform to tell if an image is real or virtual?
7) Consider a concave mirror with an object in front of the mirror. Is the image
always inverted? Is it always real? Give conditions for your answer. Use
your notes or use your drawings from question 1.
8) If you were designing a shaving mirror or makeup mirror would you make it
convex or concave? Explain why in detail.
Answers:
1) You know you are doing it right if you are getting answers in the following
ranges a. -1<M<0
b. M = 1
c. M<-1
d. No image e. M>1
2) a. M>1
b. M<-1
3) a,b.
0<M<1