Optics quiz #2

Optical Centre (O)

Middle of the lens — no bending here.

Principal Axis

Straight line through the center and both focal points.

Focus/Focal Point (F)

Where light rays meet (or seem to).

F vs. F’

F is in front; F’ is behind the lens.

Converging Lens (Convex)

Bends light inward to a point.

Diverging Lens (Concave)

Spreads light outward.

Converge

Light rays coming together.

Diverge

Light rays spreading apart.

Parallel

Rays going same way, same spacing.

Perpendicular

At a 90° angle.

Emergent Ray

Ray that comes out after refraction.

Normal

Imaginary 90° line to a surface.

Refraction

Light bends changing mediums (like air to water).

Partial Reflection

Some light reflects, some bends.

Internal Reflection

All light bounces inside (no bending out).

Critical Angle

the angle of incidence where the angle of refraction is 90°

Angle of Incidence (θi)

angle between incident ray and normal.

Angle of Reflection (θr)

angle between the reflected ray and the normal.

Angle of Refraction (θR)

angle between the refracted ray and the normal

Index of Refraction

Number showing how much light slows down.

Medium

What light travels through (air, water, etc.).

Vacuum

Empty space — light is fastest here.

Apparent Depth

Looks shallower than it is (because of refraction).

Dispersion

White light splitting into colors (rainbow effect).

SALT

Size, Attitude (↑ or ↓), Location, Type (real or virtual).

Magnification (M)

hi ÷ ho (how big the image is vs object).

Object Height (ho)

How tall the real object is.

Image Height (hi)

How tall the image is.

Object Distance (do)

From object to lens or mirror.

Image Distance (di)

From image to lens or mirror.