MODULE 3: REFLECTION AND REFRACTION OF LIGHT IN MIRROR

the incoming light wave

incident wave

the wave that is bounced away from the surface.

reflected wave

___ are bent

Refracted light waves

an optical phenomenon that occurs when a ray of

light strikes a medium boundary at an angle larger than a particular critical

angle with respect to the normal to the surface.

total internal reflection

the angle of incidence above which total internal reflection

occurs.

critical angle

Normally to a flat surface is a vector that is perpendicular to that surface.

To a non-flat surface at point P on the surface is a vector perpendicular to

the ___ to that surface at P.

tangent plane to

The production of an image by a mirror.

reflection

Something, such as ___, that is reflected.

light, radiant heat, sound, or an image

The change in direction of a wave, such as a light or

sound wave, away from a boundary the wave

encounters.

reflection

___ remain in their original medium

rather than entering the medium they encounter.

reflected waves

According to the law of reflection, the angle of reflection of a reflected wave is

___

equal to its angle of incidence.

Light is reflected in all directions.

diffuse reflection

This is caused by a surface that isn’t smooth.

diffuse reflection

All the light travelling in one direction and reflecting from the mirror is

reflected in one direction.

specular reflection

the single point where light from the object hits or is focused.

focal point

Located half the distance from the mirror to the center of curvature.

focal point

the distance from the reflecting surface to the focal point.

focal length

formed when the incident and the reflected rays intersect in front of

the mirror.

real

does not actually exist (no light is produced). Occur at points where

extensions from incident and reflected rays converge behind the mirror.

virtual

the center of that original sphere.

center of curvature

the radius of the sphere.

radius of curvature

the point where the mirror crosses the principal axis.

vertex

a line drawn through the vertex, focus and center of

curvature.

principal axis

A mirror with a flat surface.

plane mirrors

Properties of an image in a plane mirror.

➢ The image is upright.

➢ The image is the same size as the object.

➢ The image is the same distance from the mirror as the object appears

to be.

➢ The image is virtual, not real, because the light rays do not actually

pass through the image.

A piece cut out of a reflective sphere.

spherical mirrors

Either concave or convex.

spherical mirrors

Image is virtual and upright.

convex mirrors or diverging mirror

Used for security in stores and on the passenger side of many cars.

convex mirrors or diverging mirror

Light rays that strike the mirror surface are reflected so that they diverge, or “go apart,” and they never come to a point.

convex mirrors or diverging mirror

The focal length is negative.

convex mirrors or diverging mirror

The object and focus are on opposite sides of the mirror.

convex mirrors or diverging mirror

All images are smaller than the object.

convex mirrors or diverging mirror

Can have either real or virtual images.

concave mirror or converging mirror

Light rays that strike the mirror surface are reflected so that they ___ at a point.

converge, or “come together,”

focal length is positive

concave mirror or converging mirror

The object and the focus are on the same side of the mirror.

concave mirror or converging mirror

the mirror equation

1/do + 1/di = 1/f

In most cases the height of the image differs from the height of the object.

This means that the mirror has done some ___

magnifying or reducing.

The ratio of the image height to the object height, which is closely related

to the ratio of the image distance to the object distance.

M = hi/ho = -di/do

If magnification is 1 then the object and the image are ___. If

m>1 then the image is ___. If m<1 then the image is ___

the same size, larger, smaller

the sign conventions

CONCAVE MIRROR

f = positive

di = positive if the image is real

hi = negative if the image is inverted

f = positive

di = negative if the image is virtual

hi = positive if the image is upright

CONVEX MIRROR

f = negative

di = negative

hi = positive