AP Physics 2: Algebra-Based Flashcards: Refraction
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 14 cards to help you master important concepts.
State the equation for Snell's Law.
The equation is $n_1\sin\theta_1 = n_2\sin\theta_2$.
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State the equation for Snell's Law.
The equation is $n_1\sin\theta_1 = n_2\sin\theta_2$.
If medium A has a higher index of refraction than medium B, in which medium does light travel slower?
Light travels slower in medium A, because the index of refraction is inversely proportional to the speed of light.
State the equation for the index of refraction.
The equation is $n = \frac{c}{v}$, where c is the speed of light in a vacuum and v is the speed of light in the medium.
What is the critical angle (θc)?
The critical angle is the angle of incidence above which total internal reflection occurs. At the critical angle, the angle of refraction is 90 degrees.
A light ray travels from glass ($n_1=1.5$) to air ($n_2=1.0$). Will total internal reflection be possible?
Yes, total internal reflection is possible because the light is traveling from a medium with a higher index of refraction to one with a lower index of refraction ($n_1 > n_2$).
What relationship does Snell's Law describe?
Snell’s law relates the angles of incidence and refraction to the indices of refraction of the two media through which a light ray passes.
What is refraction?
Refraction is the change in direction of a light ray as it passes from one medium into another.
Under what condition can total internal reflection occur?
Total internal reflection can only occur when light travels from a medium with a higher index of refraction into a medium with a lower index of refraction.
When light passes from a medium of lower index of refraction to one of higher index, does it bend toward or away from the normal?
The light ray slows down and bends toward the normal.
State the equation used to find the critical angle for total internal reflection.
The equation is $\sin\theta_c = \frac{n_2}{n_1}$, where light is traveling from medium 1 to medium 2 and $n_1 > n_2$.
What is total internal reflection?
Total internal reflection is a phenomenon where a light ray is completely reflected at the boundary between two media, rather than being refracted.
When light passes from a medium of higher index of refraction to one of lower index, does it bend toward or away from the normal?
The light ray speeds up and bends away from the normal.
Define the index of refraction (n).
The index of refraction is a value that describes how much light slows down in a medium; it is inversely proportional to the speed of light in that medium.
What is the underlying cause of refraction?
Refraction is caused by the change in the speed of light as it travels from one medium into another.