(455) Reflection and refraction [IB Physics SL/HL]

Definition: Reflection occurs when light bounces off a surface.
Angles of Incidence and Reflection:
- Angle of incidence (Theta 1) equals angle of reflection (Theta 2).
- Angles are measured from the normal (line perpendicular to the surface).

Definition: Refraction is the bending of light as it passes from one medium to another due to a change in speed.
Speed Changes: Light can speed up or slow down depending on the optical density of the mediums involved.
Index of Refraction (n):
- Air has an index of refraction of approximately 1.
- Water has an index of refraction around 1.33.
Frequency and Wavelength:
- Frequency remains constant when light enters a new medium.
- Speed and wavelength change depending on the medium.
Snell's Law:
- Formula: n1/n2 = sin(Theta2)/sin(Theta1)
- Describes behavior of light as it transitions between mediums.

Critical Angle: The angle at which the refracted ray makes an angle of 90 degrees with the normal.
Total Internal Reflection: Occurs when the incident angle exceeds the critical angle, causing light to reflect entirely back into the medium.

Wavelength of Light: Changes inversely to the index of refraction as it enters different mediums.
Example: As light goes from a medium with higher n to a lower n, the wavelength increases.
Conclusion: Wavelength, speed, and angles act oppositely to the index of refraction values.