AP Physics 2 : Mirrors

Study concepts, example questions & explanations for AP Physics 2

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Example Questions

Example Question #431 : Ap Physics 2

An object of height  is placed  in front of a concave mirror that has a radius of curvature of 

Determine the focal length of the mirror.

Possible Answers:

Correct answer:

Explanation:

Use the mirror/lens equation:

Where:

 is the object distance from the mirror, which is taken to be negative

 is the image distance from the mirror

 is the focal length of the mirror, which for concave mirrors is taken to be positive

 is the radius of curvature of the mirror

Plug in values and solve for the focal point:

Example Question #11 : Optics

An object of height  is placed  in front of a concave mirror that has a radius of curvature of 

Determine the distance of the image.

Possible Answers:

Correct answer:

Explanation:

Use the mirror/lens equation:

Where:

 is the object distance from the mirror, which is taken to be negative

 is the image distance from the mirror

 is the focal length of the mirror, which for concave mirrors is taken to be positive

 is the radius of curvature of the mirror

Plug in values and solve for the image distance:

Example Question #431 : Ap Physics 2

An object of height  is placed  in front of a concave mirror that has a radius of curvature of . Will the image be real or virtual?

Possible Answers:

Virtual

There will be no image

Cannot be determined without knowing the index of refraction

Real

Correct answer:

Virtual

Explanation:

Use the relationship between focal length and radius:

Plug in values.

Based on the properties of a concave mirror, objects inside the focal length of the mirror will generate virtual images.

Example Question #22 : Optics

An object of height  is placed  in front of a convex mirror that has a radius of curvature of .

Determine the magnification of the image.

Possible Answers:

Correct answer:

Explanation:

Use the mirror/lens equation:

Where:

 is the object distance from the mirror, which is taken to be negative number

 is the image distance from the mirror

 is the focal length of the mirror, which for convex mirrors is taken to be negative number

 is the radius of curvature of the mirror

Plug in values:

Solve for :

Use the equation for magnification and solve for magnification, :

Example Question #14 : Mirrors

An object of height  is placed  in front of a concave mirror that has a radius of curvature of

Determine the size of the image.

Possible Answers:

Correct answer:

Explanation:

Use the mirror/lens equation:

Where:

 is the object distance from the mirror, which is taken to be negative

 is the image distance from the mirror

 is the focal length of the mirror, which for concave mirrors is taken to be positive

 is the radius of curvature of the mirror

Plug in values:

Solve for the image distance:

Use the magnification formula:

Where

 is magnification

 is image height

 is object height

Plug in values and solve for the image height:

Example Question #441 : Ap Physics 2

A ray of light is parallel to the principal axis and reflects from a concave mirror. The reflected ray will __________.

Possible Answers:

pass through both the focal point and the center of curvature

pass through the center of curvature

pass through the focal point

None of the other answers.

also be parallel to the principal axis

Correct answer:

pass through the focal point

Explanation:

Parallel rays that reflect off a concave mirror always pass through the focal point of the mirror. 

Example Question #23 : Optics

If an object is situated at a distance farther than the radius of curvature of a concave mirror, what will be true about the image formed?

Possible Answers:

The image will be real and inverted

The image will be virtual and up-right

The image will be virtual and inverted

It is impossible to determine

The image will be real and up-right

Correct answer:

The image will be real and inverted

Explanation:

In this question, we're told that an object is positioned outside of the curvature radius of a concave mirror. We're asked to identify how the resulting image will appear.

One way to approach this problem is to draw a ray diagram. In such a diagram, a straight line is first drawn from the top of the object horizontally to the mirror. From there, the line is drawn to pass through the mirror's focal point.

A second line is then drawn from the top of the object and straight through the focal point to the mirror. Then, the line is drawn horizontally away from the mirror.

The point at which these two lines intersect will represent the top of the image. In the diagram shown below, we can see that the image will appear in front of the mirror. Hence, it is a real image. Furthermore, the image appears upside down, meaning that it has an inverted orientation. So all together, the image will be real and inverted, which makes this the correct answer.

Mirror light rays

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