# Physics - Mirrors & Lenses

posted by .

When standing 1.25 m in front of an amusement park mirror, you notice that your image is three times taller. What is the radius of curvature of the mirror?

• Physics - Mirrors & Lenses -

I will assume it is an upright image, behind the mirror. The distance to the image is di = -3 do because of the 3x magnification, and do = 1.25 m. The minus sign is necessary for upright virtual images.

The focal length f is given by the equation
1/do + 1/di = 1/f
1/1.25 -1/3.75 = 2/3.75 = 1/f
Therefore f = 1.87 m.

The radius of curvature is 2f, or 3.75 m. It is a concave mirror; otherwise f would be negative.

## Similar Questions

1. ### Physics 30

An object located in front of a concave mirror with a radius of curvature of 80 cm produces an invert image that is three times the size of the object. Calculate the distance between the object and the mirror.
2. ### College Physics

An amusement park mirror shows anyone who stands 2.5 meters in front of it an upright image two times the person's height. What is the mirror's radius of curvature?
3. ### physics

A concave spherical mirror has a radius of curvature 15 cm. A 1 cm tall bulb is placed in front of the mirror such that its image is formed 10 cm in front of the mirror. If you measure distance from the optic center of the mirror, …
4. ### physics ---

A concave spherical mirror has a radius of curvature 15 cm. A 1 cm tall bulb is placed in front of the mirror such that its image is formed 10 cm in front of the mirror. If you measure distance from the optic center of the mirror, …
5. ### physics

A convex mirror in an amusement park has a radius of curvature of 3.00m. A man stands in front of the mirror so that his image is half as tall as his actual height. At what distance must the man focus his eyes in order to see his image?
6. ### physics

A 4.5 cm tall object is placed 20 cm in front of a spherical mirror. It is desired to produce a virtual image that is upright and 3.5 cm tall. (a) What type of mirror should be used?
7. ### Physics

A concave makeup mirror is designed so that a person 25.3 cm in front of it sees an upright image at a distance of 54.0 cm behind the mirror. a) What is the radius of curvature of the mirror?
8. ### physics

A person stands in front of a mirror at an amusement park. the person is left of a mirror. the mirror shows an upright image of the person that seems to be 4.0 meters behind the mirror. assume the image is 3.5 times the person's height. …
9. ### college physics

A reflecting telescope has a radius of curvature of 3m for its objective mirror and a radius of curvature of -1.5 for its eyepiece mirror. If the distance between the two mirrors is 0.90 m, how far in front of the eyepiece should you …
10. ### physics

A convex spherical mirror has a radius of curvature of 50 cm. Determine the position and magni cation of the image of an object located 35 cm in front of the mirror. i only know how to do concave mirrors. i have the equations as 1/f=1/d0+1/di …

More Similar Questions