Question 1

According to Fermat's Principle of Least Time, how does light travel between two points in a uniform medium?

Accepted Answer

Light travels along the path that minimizes the time taken between the two points.

Question 2

In a uniform medium, what is the relationship between the time $$t$$ taken by light to travel a distance $$d at $$speed $$v$$?

Accepted Answer

$$t = \frac{d}{v}$$

Question 3

When light reflects off a flat mirror, which statement about the angles of incidence ($$	heta_i) $$and reflection ($$	heta_r) is $$correct?

Accepted Answer

$$	heta_i = 	heta_r$$

Question 4

A person sees a speck of dust in a mirror. Where does the image appear to be located?

Accepted Answer

Behind the mirror at the same distance as the object is in front

Question 5

Which phenomenon explains why a pencil appears bent when partially submerged in water?

Accepted Answer

Refraction

Question 6

What is the physical meaning of the refractive index $$n of a $$material?

Accepted Answer

It is the ratio of the speed of light in vacuum to the speed of light in the material.

Question 7

Which equation correctly represents Snell's Law for refraction at the boundary between two media?

Accepted Answer

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

Question 8

If a light ray passes from air ($$n=1.00) $$into water ($$n=1.33) at an $$angle of $$30^\circ to $$the normal, what is the angle of refraction in the water?

Accepted Answer

$$22.0^\circ$$

Question 9

Which of the following best describes total internal reflection?

Accepted Answer

Light is completely reflected back into the medium when the angle of incidence exceeds the critical angle.

Question 10

A diamond ($$n=2.42) is $$surrounded by air ($$n=1.00). $$What is the critical angle for total internal reflection at the diamond-air boundary?

Accepted Answer

$$24.4^\circ$$

Question 11

Why does visible light pass through glass while ultraviolet (UV) and infrared (IR) are often absorbed?

Accepted Answer

Visible light generates low-energy vibrations in glass molecules, while UV and IR generate high-energy vibrations that are absorbed.

Question 12

A ray of light travels from water ($$n=1.33) $$into air ($$n=1.00). If $$the angle of incidence is $$50^\circ$$, will total internal reflection occur?

Accepted Answer

Yes, because $$50^\circ is $$greater than the critical angle for water-air.

Question 13

Which real-world application relies on total internal reflection?

Accepted Answer

Fiber optic communication cables

Question 14

A light ray in air strikes a glass prism ($$n=1.50) at$$ $$45^\circ to $$the normal. What is the angle of refraction inside the glass?

Accepted Answer

$$28.1^\circ$$

Question 15

Which statement best explains why images in a flat mirror appear to be the same size as the object?

Accepted Answer

The proportions of the object are maintained due to the law of reflection.

Question 16

If a ray of light passes from diamond ($$n=2.42) $$into water ($$n=1.33$$), what is the critical angle for total internal reflection?

Accepted Answer

$$33.4^\circ$$

Question 17

Which of the following is NOT a consequence of light interacting with matter?

Accepted Answer

Diffusion

Question 18

A person running from sand to water wants to minimize travel time. Which path should they take according to Fermat's Principle analogy?

Accepted Answer

A path that spends more time in the faster medium (water)

Question 19

Which optical phenomenon causes the splitting of white light into a spectrum when passing through a prism?

Accepted Answer

Dispersion

Physics 12: Consequences of Light Interacting with Matter – Reflection, Refraction, and Optical Illusions

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