Optics I: Reflection & Mirrors

Luminous (definition)

A luminous object is one which emits light. E.g. stars, bioluminescent organisms, fire

Non-luminous (definition)

A non-luminous object is one which does not emit light. E.g. the moon, Road signs, cat's eyes(road lights)

Lateral inversion (definition)

The way things look back to front in a mirror

Real image features

Formed in front of a mirror, can be trapped on a piece of paper, formed by rays of light which actually cross

Virtual image features

Formed behind a mirror, cannot be trapped on a piece of paper, formed by rays of light which appear to cross

First rule for drawing concave/converging mirror diagrams

A ray of light which enters the mirror parallel to the principal axis will be reflected in the principal focus

Second rule for drawing concave/converging mirror diagrams

A ray of light which enters the mirror through the principal focus will be reflected parallel to the principal axis

Third rule for drawing concave/converging mirror diagrams

A ray light which enters the mirror as if it had come from the centre of curvature will be reflected back on its own path

The first law of reflection (definition)

The first law of reflection states that the incident ray, the normal and reflected ray are co-planer

The second law of reflection (definition)

The second law of reflection states that the angle of incidence is equal to the angle of reflection

Concave/converging mirror (Object is outside C) Image features

Image is: diminished, inverted, real

Concave/converging mirror (Object is at C) Image features

Image is same size, inverted, real

Concave/converging mirror (Object is between C and F) Image features

Image is magnified, inverted, real

Concave/converging mirror (Object is at F) Image features

Image is at infinity(lemniscate), nothing seen in mirror/white sheen

Concave/converging mirror (Object is between F and P) Image features

Image is magnified, upright/erect, virtual

Concave/converging mirror (Object is between F and P) Image features

Image is magnified, upright, virtual

Concave/converging mirror diagram, (Object is outside C)

Draw Concave/converging mirror diagram (Object is at C)

Draw Concave/converging mirror diagram (Object is between C and F)

Draw Concave/converging mirror diagram (Object is at F)

Draw Concave/converging mirror diagram (Object is between F and P)

What does i mean in the second law of reflection?

Angle of incidence

What does r mean in the second law of reflection?

Angle of reflection

Draw the Ray diagram for convex mirror

3 uses of concave/converging mirrors

Shaving or make up mirrors, dentist mirrors, car headlamp reflectors

3 uses of convex/diverging mirrors

On bad bends in roads, security mirrors in shops, car mirrors

Convex mirrors advantage over plane mirrors

Have a wider field of view

Focal length formula

1/f = 1/u +1/v

Magnification formula

m= v/u

f

Focal length (between F + P)

u

Object distance

v

Image distance

m

Magnification

Convention of signs (u)

u is always +VE (positive)

Convention of signs (v)

v is +VE for real images but -VE (-NE) for virtual images

Convention of signs (f)

f is +VE for concave/converging mirrors but -VE for convex/diverging mirrors.

Convention of signs (m)

m is +VE for inverted images but -VE for upright/erect images

Image features for convex mirrors

Image is diminished, upright, virtual

Reflection (definition)

The rebounding of light off of surfaces