LIGHT AND SIGHTLIGHT AND SIGHTBY: EN. KAMARUZAMAN BIN ABD SAMADBY: EN. KAMARUZAMAN BIN ABD SAMAD

PROPERTIES OF LIGHT

Travel in straight lineCan be reflect

Can be disperse

Can be refract

REFLECTION

1- Light bounce the surface of object

2- i (incident angle) = r (reflected angle)

3- Properties image on plane mirror

upright

Same size

virtual

i r

REFRACTION

speed of light change when pass from one medium to

another medium in different density

90 o line (normal)

AIR

WATER

90 o line (normal)

AIR

WATER

AIR

WATER

AIR

WATER

DEFECT OF VISIONDEFECT OF VISION& &

LIMITATION OF SIGHTLIMITATION OF SIGHT

Learning ObjectiveLearning Objective

At the end of the lesson the students must able:

1- Describe the defect of vision2- State the limitation of sight.

Close object blur Distant object clear Sharp image form behind the

retina Caused:

◦ Eyeball – too short◦ Eye-lens – too thin

Overcome: convex lens

DEFECT OF VISIONDEFECT OF VISIONSHORT-SIGHTEDNESS

(MYOPIA)LONG-SIGHTEDNESS

(HYPERMETROPIA)

Close object clear Distant object blur Sharp image form in front of

retina Caused:

◦ Eyeball – too long◦ Eye-lens – too thick

Overcome: concave lens

Distant object

Near object

Continue…Continue…

SHORT-SIGHTEDNESS(MYOPIA)

LONG-SIGHTEDNESS

(HYPERMETROPIA)

Distant object

Near object

Distant object

Near object

SOLUTION SOLUTION

Continue…Continue…

DEFECT OF VISION

- Genetic disease.

- Lack photoreceptor on retina.

- Can’t determine red and

green.

-

-Caused by irregular surface of

cornea.

- Sees some part of object more

clearly than other part.

- Correction:

-Surgery

-Special lens

Colour blindness Astigmatism

LIMITATION OF SIGHT

We can’t see tiny object We can’t see distant object

We can’t see through opaque object

OPTICAL ILLUSION

Image form in accurate but misinterpreted by brain

BLIND SPOT

Eye cannot detect image that fall on the spot

Do You See the Bunny or the Duck? Do You See the Bunny or the Duck?

What do you see What do you see at first an old at first an old lady or a young lady or a young woman?woman?