AP Physics 2 Flashcards: Refraction

What this deck covers

This deck focuses on Refraction, giving you a quick way to review the definitions, rules, and examples that matter most for AP Physics 2.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is the effect of refraction on a straight object in water?

Answer: The object appears bent or displaced at the surface. Light bends at the interface, creating optical illusion.

Flashcard 2: What happens to the speed of light as it enters a denser medium?

Answer: The speed of light decreases. Light slows down in optically denser media.

Flashcard 3: Find the critical angle for water-air interface with $n_{\text{water}} = 1.33$.

Answer: $\theta_c = \text{sin}^{-1}(\frac{1}{1.33})$. Uses $\theta_c = \sin^{-1}(\frac{n_2}{n_1})$ with $n_2 = 1$.

Flashcard 4: Calculate the wavelength in glass ($n=1.5$) if $\text{wavelength in air} = 600 \text{nm}$.

Answer: $\text{Wavelength in glass} = \frac{600 \text{nm}}{1.5}$. Wavelength scales inversely with refractive index.

Flashcard 5: What is the relationship between refractive index and optical density?

Answer: Higher refractive index means higher optical density. Higher $n$ means light travels slower in that medium.

Flashcard 6: What is dispersion?

Answer: The separation of light into colors by refraction. Different wavelengths refract by different amounts.

Flashcard 7: What is total internal reflection?

Answer: When light reflects entirely back into a medium beyond the critical angle. Occurs when angle exceeds critical angle in denser medium.

Flashcard 8: Find the critical angle for water-air interface with $n_{\text{water}} = 1.33$.

Answer: $\theta_c = \text{sin}^{-1}(\frac{1}{1.33})$. Uses $\theta_c = \sin^{-1}(\frac{n_2}{n_1})$ with $n_2 = 1$.

Flashcard 9: Which color of light refracts the least?

Answer: Red light refracts the least. Red has lowest frequency and refracts least.

Flashcard 10: Which color of light refracts the most?

Answer: Violet light refracts the most. Violet has highest frequency and refracts most.

Flashcard 11: Calculate the wavelength in glass ($n=1.5$) if $\text{wavelength in air} = 600 \text{nm}$.

Answer: $\text{Wavelength in glass} = \frac{600 \text{nm}}{1.5}$. Wavelength scales inversely with refractive index.

Flashcard 12: Identify the phenomenon when light passes through a prism.

Answer: Dispersion occurs, separating light into colors. Different colors refract at different angles through prism.

Flashcard 13: What is the refractive index of a vacuum?

Answer: The refractive index of a vacuum is 1. Vacuum is the reference medium with $n = 1$.

Flashcard 14: What is the formula for the refractive index in terms of speed?

Answer: $n = \frac{c}{v}$. Defines refractive index as ratio of speeds.

Flashcard 15: What is the main cause of chromatic aberration in lenses?

Answer: Chromatic aberration is caused by dispersion. Different colors focus at different points due to dispersion.

Flashcard 16: How does wavelength change when light enters a denser medium?

Answer: Wavelength decreases. Frequency stays constant, so $\lambda = \frac{v}{f}$ decreases as $v$ decreases.

Flashcard 17: What occurs when light passes from a less dense to a more dense medium?

Answer: Light bends toward the normal. Higher optical density causes light to bend toward the normal.

Flashcard 18: Find the angle of refraction for light moving from air to water at $45^\text{o}$. ($n_{\text{water}}=1.33$)

Answer: $\theta_2 = \text{sin}^{-1}(\frac{\text{sin}(45^\text{o})}{1.33})$. Light bends toward normal when entering denser medium.

Flashcard 19: What is the apparent depth of an object underwater?

Answer: Apparent depth is less than actual depth due to refraction. Light bends away from normal when exiting water.

Flashcard 20: What is the principle of reversibility in refraction?

Answer: Light will follow the same path if its direction is reversed. Light paths are reversible due to symmetry of physics.

Flashcard 21: Which color of light refracts the least?

Answer: Red light refracts the least. Red has lowest frequency and refracts least.

Flashcard 22: Which color of light refracts the most?

Answer: Violet light refracts the most. Violet has highest frequency and refracts most.

Flashcard 23: What is the definition of refraction?

Answer: Refraction is the bending of light as it passes from one medium to another. Light changes direction when moving between media with different optical densities.

Flashcard 24: Determine the angle of refraction if $n_1=1.5$, $n_2=1.0$, and $\theta_1=45^\text{o}$.

Answer: $\theta_2 = \text{sin}^{-1}(1.5 \times \text{sin}(45^\text{o}))$. Light exits glass into air, bending away from normal.

Flashcard 25: What is the relationship between refractive index and optical density?

Answer: Higher refractive index means higher optical density. Higher $n$ means light travels slower in that medium.

Flashcard 26: What is the effect of refraction on the shape of a swimming pool viewed from above?

Answer: The pool appears shallower due to refraction. Refraction makes objects appear closer to surface.

Flashcard 27: How does temperature affect the refractive index of gases?

Answer: Refractive index decreases with increasing temperature. Higher temperature decreases gas density, reducing $n$.

Flashcard 28: Identify the unit of the index of refraction.

Answer: The index of refraction is dimensionless. It's a ratio of speeds, so no units.

Flashcard 29: What happens to the speed of light as it enters a denser medium?

Answer: The speed of light decreases. Light slows down in optically denser media.

Flashcard 30: State the relationship between frequency and speed of light in a medium.

Answer: Frequency remains constant; speed changes. Energy conservation requires frequency to remain constant.

Flashcard 31: What is total internal reflection?

Answer: When light reflects entirely back into a medium beyond the critical angle. Occurs when angle exceeds critical angle in denser medium.

Flashcard 32: What does the index of refraction represent?

Answer: The index of refraction measures how much light slows in a medium. Compares light speed in a medium to speed in vacuum ($c$).

Flashcard 33: What is the critical angle?

Answer: The angle of incidence at which light is refracted along the boundary. Beyond this angle, total internal reflection occurs instead.

Flashcard 34: Calculate the speed of light in water ($n=1.33$).

Answer: $v = \frac{c}{1.33}$. Light speed equals vacuum speed divided by refractive index.

Flashcard 35: Identify the effect of frequency on refraction.

Answer: Higher frequency light refracts more than lower frequency. Higher frequency means higher energy and greater refraction.

Flashcard 36: What is the formula for the speed of light in a medium?

Answer: $v = \frac{c}{n}$. Relates medium speed to vacuum speed through refractive index.

Flashcard 37: State the effect of increasing wavelength on the angle of refraction.

Answer: Increasing wavelength decreases the angle of refraction. Longer wavelengths have lower refractive indices.

Flashcard 38: What happens to the direction of light when it passes through a rectangular glass block?

Answer: The light exits parallel to its original path. Parallel entry and exit with lateral displacement only.

Flashcard 39: State Snell's Law formula.

Answer: $n_1 \times \text{sin}(\theta_1) = n_2 \times \text{sin}(\theta_2)$. Relates incident and refracted angles through refractive indices.

Flashcard 40: Find the angle of refraction for light moving from air to water at $45^\text{o}$. ($n_{\text{water}}=1.33$)

Answer: $\theta_2 = \sin^{-1}(\frac{\sin(45^\text{o})}{1.33})$. Light bends toward normal when entering denser medium.

Flashcard 41: What is the principle of reversibility in refraction?

Answer: Light will follow the same path if its direction is reversed. Light paths are reversible due to symmetry of physics.

Flashcard 42: What is the phenomenon when the sun appears before its rise due to refraction?

Answer: This phenomenon is called atmospheric refraction. Light bends through varying atmospheric density layers.

Flashcard 43: What is the formula for the speed of light in a medium?

Answer: $v = \frac{c}{n}$. Relates medium speed to vacuum speed through refractive index.

Flashcard 44: What is the definition of refraction?

Answer: Refraction is the bending of light as it passes from one medium to another. Light changes direction when moving between media with different optical densities.

Flashcard 45: What occurs when light passes from a more dense to a less dense medium?

Answer: Light bends away from the normal. Lower optical density causes light to bend away from the normal.

Flashcard 46: Find the angle of refraction when light enters glass ($n=1.5$) from air at $30^\text{o}$.

Answer: $\theta_2 = \text{sin}^{-1}(\frac{\text{sin}(30^\text{o})}{1.5})$. Applies Snell's law with $n_1 = 1$ and $n_2 = 1.5$.

Flashcard 47: What is the critical angle?

Answer: The angle of incidence at which light is refracted along the boundary. Beyond this angle, total internal reflection occurs instead.

Flashcard 48: What occurs when light passes from a less dense to a more dense medium?

Answer: Light bends toward the normal. Higher optical density causes light to bend toward the normal.

Flashcard 49: Calculate the refractive index of a medium if $c=3\times10^8 \text{m/s}$ and $v=2\times10^8 \text{m/s}$.

Answer: $n = \frac{3\times10^8}{2\times10^8} = 1.5$. Direct calculation using $n = \frac{c}{v}$.

Flashcard 50: State the relationship between frequency and speed of light in a medium.

Answer: Frequency remains constant; speed changes. Energy conservation requires frequency to remain constant.

Flashcard 51: What does the index of refraction represent?

Answer: The index of refraction measures how much light slows in a medium. Compares light speed in a medium to speed in vacuum ($c$).

Flashcard 52: Identify the cause of a mirage.

Answer: A mirage is caused by refraction of light in varying air densities. Temperature gradients create layers with different refractive indices.

Flashcard 53: What is the phenomenon when the sun appears before its rise due to refraction?

Answer: This phenomenon is called atmospheric refraction. Light bends through varying atmospheric density layers.

Flashcard 54: Calculate the speed of light in water ($n=1.33$).

Answer: $v = \frac{c}{1.33}$. Light speed equals vacuum speed divided by refractive index.

Flashcard 55: What is dispersion?

Answer: The separation of light into colors by refraction. Different wavelengths refract by different amounts.

Flashcard 56: What is the effect of refraction on an image through a lens?

Answer: The image can be magnified or minimized. Refraction at curved surfaces creates optical magnification effects.