LIGHT AND ITS USES

LIGHT RAY

STRAIGHT LINE

PATH OF LIGHT

RAY MODEL OF LIGHT

• THE RAY MODEL OF LIGHT ASSUMES LIGHT

RAYS SPREAD OUT IN ALL DIRECTIONS IN

STRAIGHT-LINE PATHS CALLED LIGHT RAYS.

• AN IMAGE IS FORMED WHEN THE LIGHT

RAYS LEAVING THE OBJECT FROM THE SAME

POINT MEET.

SHADOWS

• SHADOWS OCCUR BECAUSE LIGHT

TRAVELS IN STRAIGHT LINES

• IF AN OBJECT GETS INTO THAT BEAM,

THE OBJECT BLOCKS SOME OF THE

LIGHT & A SHADOW IS CREATED.

REFLECTION OF LIGHT

WHEN LIGHT STRIKES A SURFACE,

SOME OF THE LIGHT BOUNCES BACK

(IS REFLECTED). THE REST IS EITHER

ABSORBED BY THE MATERIAL OR

TRANSMITTED THROUGH IT.

REFLECTION OF LIGHT

LAW OF REFLECTION

• LIGHT WILL BE REFLECTED

OFF A SURFACE AT THE SAME

ANGLE AS IT STRIKES THE

SURFACE.

THE TYPE OF SURFACE THE LIGHT STRIKES

DETERMINES THE KIND OF REFLECTION

SURFACE TEXTURE

SMOOTH SURFACE = RAYS HIT AT

THE SAME ANGLE, THUS ARE

REFLECTED AT THE SAME ANGLE.

THIS IS CALLED

REGULAR REFLECTION

WHEN THE SURFACE IS NOT SMOOTH, OR

IRREGULAR, EACH LIGHT RAY HITS THE

SURFACE AT A DIFFERENT ANGLE.

THIS IS CALLED

DIFFUSE REFLECTION

IT STILL OBEYS THE LAW OF REFLECTION,

SO EACH RAY IS REFLECTED AT A

DIFFERENT ANGLE FROM THE OTHERS.

THE REFLECTED RAYS ARE SCATTERED IN

ALL DIRECTIONS

DIFFUSE

REFLECTION

MIRRORS

PLANE MIRROR

• MIRROR WITH A VERY, VERY, VERY, VERY, VERY FLAT

SURFACE• EX: WALL OR POCKET MIRROR

CHARACTERISTICS OF PLANE MIRRORS

• THE IMAGE IS RIGHT SIDE UP

• THE IMAGE IS THE SAME SIZE AS THE

ORGINAL OBJECT

• LEFT & RIGHT ARE REVERSED

• THE IMAGE APPEARS TO BE ON THE OTHER SIDE

OF THE MIRROR = VIRTUAL IMAGE (NOT REAL)

VIRTUAL IMAGE

• THE LIGHT RAYS REFLECTED DON’T

ACTUALLY MEET, BUT THE IMAGE SEEMS

TO BE LOCATED WHERE THE LIGHT RAYS

WOULD MEET

• MEANS NOT REAL; THE IMAGE CAN ONLY

BE SEEN IN THE MIRROR

CONCAVE MIRRORS

• SURFACE CURVES INWARD

• LIGHT RAYS COMING IN PARALLEL ALL REFLECT THROUGH

THE SAME POINT IN FRONT OF

THE MIRROR

• MAY BE A VIRTUAL OR REAL IMAGE & MAY BE INVERTED OR

UPRIGHT DEPENDING ON THE LOCATION OF THE OBJECT IN

RESPECT TO THE

FOCAL POINT

EX: MAKE-UP MIRRORS

FOCAL POINT

• THE POINT IN FRONT OF

THE MIRROR WHERE THE

REFLECTED RAYS MEET

PLANE MIRROR

CONCAVE MIRRORWITH AN OBJECT REFLECTED

FROM A DISTANCE

CONCAVE MIRROR RAYS, FOCAL POINT, AND CENTER

CONCAVE MIRROR

WITH THE OBJECT REFLECTED

LOCATED INSIDE THE FOCAL POINT

OBJECT

“VIRTUAL” IMAGE

CONCAVE MIRROROBJECT BETWEEN FOCAL POINT & MIRROR

CONVEX MIRROR

• SURFACE CURVES OUTWARD

• REFLECTED RAYS SPREAD OUT

FROM THE SURFACE

• IMAGE RIGHT SIDE UP AND

SMALLER THAN THE ORIGINAL OBJECT

• VIRTUAL IMAGE

• USED IN CARS & STORE SECURITY