Chapter 15 Refraction Section 1 Refraction Refraction of

Chapter 15 Refraction

Section 1 Refraction

Refraction of Light • Is the bending of a wave disturbance as it passes (at an angle) from one medium into another • Occurs because velocity changes

Refraction

Refraction of Light • If the light ray moves from a lower speed material to higher speed material, it will bend away from the normal. • If the light ray moves from a higher speed material to lower speed material, it will bend toward the normal. • No refraction occurs if the ray enters the new material parallel to the normal.

Refraction

Refraction of Light – Snell’s Law • Index of Refraction: ratio of vvacuum to vmedium n = c/v n = λo / λn Wavelength affects the index of refraction

Refraction of Light Snell’s Law: ni(sin θi) = nr(sin θr)

Refraction of Light

Refraction of Light

Section 2 Thin Lenses

Lenses What is a lens? a transparent object that refracts light rays, causing them to converge or diverge to create an image The curved surfaces change the direction of light – refraction occurs at each surface (front/back)

Types of Lenses Converging Lenses (Convex) – thicker in center Diverging Lenses (Concave) – thinner in center Where does bad light end up?

Types of Lenses - Continued Combination Lenses In prism

Lenses – Ray Drawings – 3 Rays Parallel Ray: is incident parallel to principal axis; refracts through to focal point Central Ray: incident through center of lens; travels straight through lens Focal Ray: incident through the focal point; refracts parallel to principal axis What do you call someone who studies physics?

Ray Drawings – Addressing Refraction A physician

Lenses – Ray Drawings – 3 Rays Parallel Ray: is incident parallel to principal axis; refracts through to focal point Central Ray: incident through center of lens; travels straight through lens Focal Ray: incident through the focal point; refracts parallel to principal axis Who’s the sickest rapper alive?

Image Location for a Converging Lens Wheeze Khalafa

Image Location for a Converging Lens Note distance verbage (p, q, f) and Image/Object Identification

Image Location for a Diverging Lenses produce only VIRTUAL IMAGES

Thin-Lens Equation and Magnification Hail to the vectors

Thin Lens Combinations The image from lens 1 becomes the object for lens 2 Go ions

Section 3 Optical Phenomena

Total Internal Reflection nisin θc = nrsin 90 o but ni must be > nr so, to determine critical angle: θc = sin -1 (nr/ni)

Total Internal Reflection

Total Internal Reflection

Total Internal Reflection

Total Internal Reflection

Total Internal Reflection - Applications • Diamonds • Fiber Optics

Atmospheric Refraction

Atmospheric Refraction

Atmospheric Refraction

Dispersion

Dispersion

Dispersion

Lens Aberrations

Lens Aberrations

Lens Aberrations

Eyes and Microscopes Optical Interests

Visual Conditions – Snellen Chart

Visual Conditions – Snellen Chart

Visual Conditions

Visual Conditions (presbyopia)

Microscopes