3.9 Refraction at a plane surface

• What is refraction?

  The bending of light
• During refraction, the frequency of light remains constant.


  True
• The formula for Snell's Law is \frac{\sin(\theta_1)}{\sin(\theta_2)} = \frac{n_2}{n_1}</latex> where $\theta_{1}$ is the angle of incidence
• How is the refractive index defined?

  Ratio of light speed in vacuum to light speed in medium
• What is the refractive index of air?

  1.0003
• The higher the refractive index, the more the speed of light is reduced in that medium.


  True
• What do $\theta_{1}$ and $\theta_{2}$ represent in Snell's Law?


  Angles of incidence and refraction
• Why does light refract when it passes from one medium to another?

  Change in the speed of light
• <statement_start>$v_{1}$ and $v_{2}$ represent the speeds of light in the two media
• What is the definition of refraction?

  Bending of light
• Snell's Law is expressed as \frac{\sin \theta_{1}}{\sin \theta_{2}} = \frac{n_{2}}{n_{1}}</latex>

  True
• Snell's Law states that the ratio of the sines of the angles of incidence and refraction is equal to the ratio of the refractive indices of the two media.

  False
• What is the definition of the refractive index?

  Ratio of light speeds
• The refractive index is a dimensionless quantity.

  True
• What is the symbol for the refractive index?

  n
• When light passes from one medium to another with different refractive indices, it undergoes refraction
• The frequency of light changes when it passes from one medium to another.

  False
• What is total internal reflection used in?

  Fiber optics
• To solve problems using Snell's Law, the formula must be rearranged
• Refraction occurs because the speed of light differs
• What does Snell's Law state?

  Ratio of sines equals inverse ratio of refractive indices
• Snell's Law governs how light bends when it passes from one medium to another.


  True
• The formula for refractive index is $n =$$\frac{c}{v}$ where $c$ is the speed of light in a vacuum
• Match the material with its refractive index:

  Water ↔️ 1.33

  Glass ↔️ 1.5-1.9

  Diamond ↔️ 2.42
• When light passes from one medium to another, its frequency remains constant
• The speed of light changes when it passes from one medium to another.

  True
• What are $\theta_{1}$ and $\theta_{2}$ referred to as in the context of refraction?


  Angles of incidence and refraction
• $n_{1}$ and n_{2}</latex> denote the refractive indices of the two media.


  True
• <statement_start>In refraction, the frequency of light remains constant
• What does $\theta_{1}$ represent in Snell's Law?


  Angle of incidence
• <statement_start>Snell's Law involves the ratio of the sines of the angles of incidence and refraction
• Match the term with its description:

  $\theta_{1}$ ↔️ Angle of incidence

  $\theta_{2}$ ↔️ Angle of refraction

  $n_{1}$ ↔️ Refractive index of medium 1

  $n_{2}$ ↔️ Refractive index of medium 2
• <statement_start>The formula for the refractive index is $n =$$\frac{c}{v}$, where $c$ is the speed of light in a vacuum
• What does the refractive index measure?

  Reduction in light speed
• The higher the refractive index, the more the speed of light is reduced in that medium.


  True
• What law governs the behavior of light as it passes between two media?

  Snell's Law
• The critical angle is the angle of incidence at which the angle of refraction is 90 degrees.
• Total internal reflection occurs when light travels from a denser medium to a less dense medium at an angle greater than the critical angle.

  True
• What is the approximate angle of refraction when light travels from air to glass at an angle of incidence of 30 degrees?

  19.5 degrees