Physics 30: Chapter 5 - Lenses & Mirrors Exam

Physics 30: Chapter 5 - Lenses & Mirrors Exam

Name: ______Date: ______Mark: ____/25

Written Response. Show all your work. Clearly identify your final answer(s) rounded off to the proper number of significant digits in the chart at the bottom of the page.

Use the information below to answer question 1.

A compound microscope has two convex lenses, separated by 10.0 cm as shown in the diagram below. The objective lens has a focal length of 1.5 cm, and the eyepiece has a focal length of 6.0 cm. The object under study is placed 2.0 cm from the objective lens.

1.Using the lens formulae, calculate the

a.distance from the objective lens to the image it produces. (3 marks)

b.distance from the eyepiece to the image it produces. (3 marks)

c.microscope’s magnifying power. (1 mark)

Multiple Choice. Select the best answer and mark it clearly on your Scantron. (1 mark each)

Use the information below to answer questions 1 & 2.

An 8.0 cm tall object is placed 20 cm away from a concave mirror that has a focal length of 5.0 cm.

1.Determine the distance separating the mirror from the image.

a. / 0.15 cm
b. / 6.7 cm
c. / 0.25 cm
d. / 4.0 cm

2.Determine the image size.

a. / 2.7 cm
b. / 0.060 cm
c. / 0.10 cm
d. / 1.6 cm

Use the information below to answer questions 3 & 4.

A 10 cm tall object is placed 30 cm away from a concave lens that has a focal length of 6.0 cm.

3.Determine the distance separating the lens from the image.

a. / 0.20 cm
b. / 5.0 cm
c. / 0.13 cm
d. / 7.5 cm

4.Determine the image size.

a. / 0.067 cm
b. / 0.043 cm
c. / 1.7 cm
d. / 2.5 cm

5.A lens is used with a 2.0 cm tall object to produce an image that is 6.0 cm tall. The magnification ratio is

a. / 1.0 X
b. / 2.0 X
c. / 3.0 X
d. / 4.0 X

6.A student conducts an investigation to determine the focal length of a convex lens. She holds the lens in front of her and looks through it at a distant object. She slowly moves the lens towards her eye. She knows she is holding it a the focal length when the image

a. / is inverted
b. / is upright
c. / is real
d. / disappears

7.An object is placed 5.0 cm away from a lens. The distance between the focal point and the lens is 8.0 cm. An image is produced that is 13.3 cm away from the lens. The image type must be ______and the type of lens is ______.

i Image type / ii Lens type
a. / virtual / convex
b. / virtual / concave
c. / real / convex
d. / real / concave

8.A lens is used to produce a virtual image that is smaller than the object the lens must be a ______lens.

a. / converging
b. / diverging
c. / convex
d. / positive

9.Sir Isaac Newton developed the reflecting telescope because of chromatic aberration with telescopes that used lenses. Chromatic aberration occurs when the light does not focus at a single point because

a. / each wavelength has a different refractive index in the glass
b. / of the shape of the lens
c. / not all light bends as it travels through the glass
d. / light is a particle not a wave and therefore does not refract

10.Identify the list below that contain items that diverge light rays.

a. / Convex mirror and concave lens
b. / Convex lens and concave mirror
c. / Convex mirror and concave mirror
d. / Convex lens and concave lens

11.An experiment is conducted on a thin lens. The distance to the image and the distance to the object are measured. A graph of the inverse of the image distance as a function of the inverse of the object distance is plotted. The slope of the line is

a. / the focal length
b. / the refractive index
c. / equal to negative one
d. / magnification ratio
e. / the inverse of the focal length

12.Ray diagrams may be drawn to determine the characteristics of an image produced from a lens or mirror. When the lens produces light rays that are parallel, the image is

a. / real
b. / virtual
c. / inverted
d. / non-existent

13.The focal length of a lens is dependent on the

a. / radius of curvature of the lens
b. / material the lens is made from
c. / shape of the lens and the material it is made from
d. / location of the object used

Use the ray diagrams below to answer question 14.

14.The system(s) that would produce a virtual image is/are

a. / i and ii
b. / i and iv
c. / ii and iv
d. / iii and iv

Use the ray diagram below to answer question 15.

15.The characteristics of the image produced for an object placed beyond the focal length with the lens as shown in the diagram will be

a. / real, smaller, and upright
b. / real, smaller, and inverted
c. / virtual, smaller, and inverted
d. / virtual, smaller, and upright

16.For both lenses and mirrors, all real images are ______and all virtual images are ______.

i / ii
a. / inverted / smaller
b.@ / inverted / upright
c. / upright / smaller
d. / upright / upright

17.A lens has a focal length of –10 cm. The image produced from this lens is

a. / real and smaller than the object
b. / virtual and smaller than the object
c. / real and larger than the object
d. / virtual and larger than the object

Use the information below to answer question 18.

Light rays that enter the eye are refracted by the lens and cornea so that they focus on the back of the eye. If they do not focus on the back of the eye, as shown in the diagram below, a blurry image will result. When this occurs, glasses or contact lenses may be used to correct the vision causing the light to focus on the back of the eye.

18.The vision may be corrected in the diagram above by using a

a. / concave lens to diverge the light entering the eye
b. / concave lens to converge the light entering the eye
c. / convex lens to diverge the light entering the eye
d. / convex lens to converge the light entering the eye