Question 1

A light ray passes from air ($$n_1 = 1.00$) into water (n_2$ = 1.33) at an $$angle of incidence $$\$$theta_1$$ = 46^\circ. $$What is the angle of refraction $$\$$theta_2$$ in the water?

Accepted Answer

$$\$$theta_2$$ = 33^\circ$$

Question 2

Which equation correctly expresses Snell's Law for the refraction of light at an interface between two media?

Accepted Answer

$$n_1$$ \sin \$$theta_1$$ = $$n_2$$ \sin \$$theta_2$$

Question 3

A light ray in water ($$n_1 = 1.33$) strikes the water-air interface at 46$$^\circ$$ to the normal. What is the angle of refraction $$\$$theta_2 in $$air?

Accepted Answer

$$\$$theta_2$$ = 74^\circ$$

Question 4

What is the critical angle $$	heta_c$$ for total internal reflection at a water-air interface ($$n_{water} = 1.33$$, $$n_{air} = 1.00$$)?

Accepted Answer

$$	heta_c = 48.8^\circ$$

Question 5

Which of the following best describes total internal reflection?

Accepted Answer

It occurs when light passes from a medium with higher refractive index to one with lower refractive index at an angle greater than the critical angle.

Question 6

An optical fiber has a core of flint glass ($$n_{core} = 1.667) $$and cladding of crown glass ($$n_{cladding} = 1.523). $$What is the critical angle $$	heta_c$$ for total internal reflection at the core-cladding interface?

Accepted Answer

$$	heta_c = 66.01^\circ$$

Question 7

A camera uses a converging lens with focal length $$f = 0.0500 m. If a $$person stands $$2.50 m in $$front of the camera, what is the image distance $$d_i$$?

Accepted Answer

$$d_i = 0.0510 m$$

Question 8

Which statement about the image formed by a diverging lens is correct?

Accepted Answer

The image is always upright, virtual, and diminished.

Question 9

A $$1.70 m $$tall person stands $$2.50 m in $$front of a camera lens ($$f = 0.0500 m). $$What is the height of the image on the film?

Accepted Answer

$$h_i = -0.0347 m$$

Question 10

A ray of light in air enters an optical fiber (core $$n = 1.667) at an $$angle $$\$$theta_1$$ such that it strikes the core-cladding interface at the critical angle. If the cladding has n = 1.523$, what is the maximum value of $$\$$theta_1$$ for which total internal reflection occurs?

Accepted Answer

$$\$$theta_1$$ = 42.67^\circ$$

Question 11

Which equation is the thin lens equation?

Accepted Answer

$$\frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i}$$

Question 12

A diverging lens has a focal length $$f = -5.08 cm. An $$object is placed $$7.10 cm to $$the left of the lens. What is the image distance $$d_i$$?

Accepted Answer

$$d_i = -2.96 cm$$

Question 13

Which of the following is a correct sign convention for lenses?

Accepted Answer

For a converging lens, $$f is $$positive.

Question 14

A two-lens system consists of two converging lenses, each with $$f = 20 mm$$, separated by $$30 mm. An $$object is placed $$28 mm in $$front of the first lens. What is the final image distance from the second lens?

Accepted Answer

$$d_{i2} = 13 mm$$

Question 15

Which real-world application relies on total internal reflection in optical fibers?

Accepted Answer

Telecommunications

Question 16

If an object is placed between the focal point and a converging lens, what type of image is formed?

Accepted Answer

A virtual, upright, and magnified image

Question 17

A projector uses a converging lens to project an image onto a screen. Where should the object (slide) be placed relative to the lens to produce a real, inverted, and magnified image?

Accepted Answer

Between $$f$$ and $$2f$$ from the lens

Question 18

Which of the following best describes the image formed by a camera lens when the object is much farther than twice the focal length from the lens?

Accepted Answer

A real, inverted, and reduced image

Lecture 16

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