Deck 23: Reflection and Refraction of Light

Question 1

A light ray in air strikes a glass surface with an angle of incidence of $30.0^{\circ}$ . The angle of refraction in the glass is $20.0^{\circ}$ . What is the index of refraction of the glass?

A) 1.46
B) 1.67
C) 1.55
D) 1.52
E) 1.24

Answer 1

1.46

Question 2

A light ray in air strikes a glass surface with an angle of incidence of $30.0^{\circ}$ . The angle of refraction in the glass is $20.0^{\circ}$ . What is the speed of light in the glass?

A) $1.50 \times 10^{8} \mathrm{~m} / \mathrm{s}$
B) $2.33 \times 108 \mathrm{~m} / \mathrm{s}$
C) $2.50 \times 10^{8} \mathrm{~m} / \mathrm{s}$
D) $2.05 \times 10^{8} \mathrm{~m} / \mathrm{s}$
E) $3.00 \times 108 \mathrm{~m} / \mathrm{s}$

Answer 2

$2.05 \times 10^{8} \mathrm{~m} / \mathrm{s}$

Question 3

A light ray strikes the surface of sapphire $(n=1.77)$ at an angle of incidence of $40.0^{\circ}$ . What angle of refraction results?

A) $21.3^{\circ}$
B) $17.7^{\circ}$
C) $59.7^{\circ}$
D) $57.0^{\circ}$
E) $50.0^{\circ}$

Answer 3

$21.3^{\circ}$

Question 4

When a light ray in air enters glass with index of refraction 1.60, what is the greatest angle of refraction that can occur?

A) $0.0^{\circ}$
B) $90.0^{\circ}$
C) $52.2^{\circ}$
D) $56.2^{\circ}$
E) $38.7^{\circ}$

Question 5

When a light ray in water $(n=1.33)$ enters glass with index of refraction 1.60 , what is the greatest angle of refraction that can occur?

A) $0.0^{\circ}$
B) $52.2^{\circ}$
C) $38.7^{\circ}$
D) $56.2^{\circ}$
E) $90.0^{\circ}$

Question 6

A light goes from a material with a lower index of refraction $n_{1}$ into a material with a higher index of refraction $\mathrm{n}_{2}$ with an angle of incidence of $30.0^{\circ}$ , which of the following is true?

A) the angle of refraction is less than $30.0^{\circ}$ and total internal reflection is not possible
B) the angle of refraction is less than $30.0^{\circ}$ and total internal reflection may occur
C) the angle of refraction is more than $30.0^{\circ}$ and total internal reflection may occur
D) the angle of refraction is more than $30.0^{\circ}$ and total internal reflection is not possible

Question 7

A small object is encased in an acrylic block $(n=1.5)$ . The object appears to be $4.0 \mathrm{~cm}$ below the surface. What is the actual distance of the object below the surface?

A) $6.0 \mathrm{~cm}$
B) $2.0 \mathrm{~cm}$
C) $5.5 \mathrm{~cm}$
D) $2.7 \mathrm{~cm}$
E) $4.0 \mathrm{~cm}$

Question 8

What is the critical angle for diamond $(n=2.42)$ in air?

A) $2.42^{\circ}$
B) $67.5^{\circ}$
C) $24.4^{\circ}$
D) $65.6^{\circ}$
E) $37.1^{\circ}$

Question 9

When light ray goes through two thick rectangular slabs of glass, each of the same uniform thickness. The first slab has index of refraction $\mathrm{n}_{1}$ and the second $\mathrm{n}_{2}$ . If $\mathrm{n}_{1}<\mathrm{n}_{2}$ . How does the original angle of incidence $\theta_{\mathrm{i}}$ into the first slab compare to the final angle of refraction $\theta_{\mathrm{f}}$ where the ray leaves the second slab going back into air?

A) $\theta_{\mathrm{i}}=\left(\mathrm{n}_{1} / \mathrm{n}_{2}\right) \theta_{\mathrm{f}}$
B) $\theta_{\mathrm{i}}<\theta_{\mathrm{f}}$
C) $\theta_{\mathrm{i}}>\theta_{\mathrm{f}}$
D) $\theta_{\mathrm{i}}=\theta_{\mathrm{f}}$
E) more information is needed

Question 10

An optical fiber having index of refraction 1.40 is clad with a material of index of refraction 1.25. What is the critical angle in the fiber at the fiber-cladding interface?

A) $41.8^{\circ}$
B) $63.2^{\circ}$
C) $26.8^{\circ}$
D) $16.5^{\circ}$
E) $73.0^{\circ}$

Question 11

When light is totally polarized by reflection at an interface between two materials where the index of refraction for the incident medium is $n_{1}$ and for the other is $n_{2}$ , the incident angle is given by $\theta=\tan ^{-1}\left(n_{2} / n_{1}\right)$ . This equation holds

A) only when $n_{2}<n_{1}+1$ .
B) only when $n_{2}>n_{1}$ .
C) for all values of $n_{1}$ and $n_{2}$ .
D) only when $n_{2}>n_{1}+1$ .
E) only when $n_{1}>n_{2}$ .

Question 12

The critical angle for Lucite is $41.8^{\circ}$ . What is Brewster's angle for Lucite?

A) $48.2^{\circ}$
B) $33.7^{\circ}$
C) $56.3^{\circ}$
D) $26.3^{\circ}$
E) Brewster's angle does not exist for this material

Question 13

At what angle above the horizon would the sun appear if its reflected light from a lake, viewed at the same time, were completely polarized? $\left(\mathrm{n}_{\text {water }}=1.333\right)$

A) $53.12^{\circ}$
B) $48.75^{\circ}$
C) $23.52^{\circ}$
D) $41.25^{\circ}$
E) $36.88^{\circ}$

Question 14

As you walk at $1.5 \mathrm{~m} / \mathrm{s}$ toward a mirrored wall in a department store, how fast are approaching your image?

A) $3.0 \mathrm{~m} / \mathrm{s}$
B) $1.5 \mathrm{~m} / \mathrm{s}$
C) $6.0 \mathrm{~m} / \mathrm{s}$
D) $0.75 \mathrm{~m} / \mathrm{s}$
E) 0.0 the image stays at a constant distance

Question 15

A convex mirror has a radius of $10 \mathrm{~cm}$ . What is its focal length?

A) $-5.0 \mathrm{~cm}$
B) $5.0 \mathrm{~cm}$
C) $-10 \mathrm{~cm}$
D) $10 \mathrm{~cm}$
E) $20 \mathrm{~cm}$

Question 16

You are experimentally determining the critical angle for a novel transparent solid whose index of refraction is less than that of water $(n=1.33)$ but greater than that of air $(n=1.00)$ . Your experimental method involves underwater work in which you observe whether there is any transmitted ray at the water/solid interface as you vary the angle of incidence on the solid surface. When your device reaches an incident angle of 53 degrees you find that the transmitted ray inside the solid vanishes. What is the index of refraction for this new solid?

A) 0.57
B) 1.06
C) 1.16
D) 0.53