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Learning Introductory Physics with Activities

Paul J. Emigh, Rebecka Tumblin, Kathryn Hadley, Danielle Skinner

Section 19.8 Practice - Ray Optics

Subsection Explanation Practice

Subsection A*R*C*S Practice

Subsection Numerical practice

Problem 19.8.1. Angle of Refraction.

Light traveling from water enters a horizontal slab of glass. The light makes an angle of 20° with respect to the horizontal surface of the glass. The indexes of refraction for water and glass are \(n_{water} = 1.33\) and \(n_{glass} = 1.52\text{.}\) Calculate the angle of refraction (in degrees).
Answer.
\(55.3^{\circ}\)

Problem 19.8.2. Unknown Index of Refraction.

Light traveling from air strikes a horizontal slab of unknown material. The light makes an angle of 40° with respect to the perpendicular of the horizontal surface. The angle of refraction is measured to be about 29.4°. What is the index of refraction of this unknown material?
Answer.
1.31

Problem 19.8.3. Total Internal Reflection.

At what minimum incidence angle (in degrees) will you get total internal reflection of light that is traveling from water into a layer of ice? Note that \(n_{water} = 1.33\text{,}\) and \(n_{ice} = 1.31\text{.}\)
Answer.
\(80^{\circ}\)

Problem 19.8.4. Diverging Lens.

Consider a thin diverging lens with a focal length of 4 cm. A 2-cm-tall object is placed 8 cm in front of the lens. Use ray tracing to answer the following items:
  1. Estimate the image distance in cm.
  2. Estimate the image height in cm.
  3. Estimate the magnification
  4. Is the image real or virtual?
Answer 1.
-2.2 cm to -2.8 cm
Answer 2.
0.3 cm to 0.8 cm
Answer 3.
0.1 to 0.4
Answer 4.
Virtual

Problem 19.8.5. Magnifying Glass.

What is the focal length, in cm, of a magnifying glass (a thin converging lens) that produces a magnification of 3.00 when it is held 5.00 cm away from an object?
Answer.
7.5 cm

References References

[1]
Numerical practice activities provided by BoxSand: https://boxsand.physics.oregonstate.edu/welcome.
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