A longitudinal wave is a wave wherein the motion of the particle is parallel to the direction of the wave, while transverse wave is a wave where the motion of the particle is perpendicular to the direction of the wave.

Law of Reflection

Example: Law of Reflection

Refraction is the change in the direction of a wave due to the change in its speed/velocity

Example: Refraction of light wave

Refraction of sound wave

Refraction of water waves

Refraction of sound waves

Diffractionis the bending of a light wave as

it passes through a narrow opening, forming semicircular light waves. It occurs when water waves passes through an obstacle.

Example of diffraction

• Water waves

Diffraction of light

Diffraction of light on a silver surface

Diffraction of white light through a diffraction grating

Diffraction of light forms a rainbow pattern

INTERFERENCE

• Is simply the combination of waves passing the same medium at the same time.

• Constructive interference happens when two waves of the same frequency, in phase, and traveling in the same direction meet.• Destructive interference results when two out-

of-phase waves interfere or are in opposite directions and the combined amplitude is zero.

Interference of water waves

Interference of water waves

The constructive and destructive interference of light waves

CONVEX MIRROR

CONCAVE

Concave mirror

Convex and concave

Concave mirror

Difference between concave and convex mirrors

• Principal Axis-The principal axis is an imaginary line that cuts through the center of a mirror dividing it symmetrically in half. Imagine this as a curve on a piece of paper.

• Focal Point-The focal point is a spot on the principal axis where light would intersect if it were to strike the mirror parallel to the principal axis.

• Shape-Concave mirrors curve inward, creating a focal point in front of the mirror. Convex mirrors curve outward creating a focal point behind the mirror.

• Concave Image-Because of their shape and focal point placement, images in concave mirrors appear upside down and far away. However, when you move closer, the object enlarges. If you get close enough, the object enlarges more and the image is right-side up.

• Convex Image-In a convex mirror, images appear right-side up, shrunken and virtual, or placed somewhere behind the mirror.

• Bend-Concave mirrors bend inward, while the curvature of a convex mirror is outward.

• Concave Images-Concave mirrors reflect images upside down when viewed from afar. They also cause images to become larger when viewed from close up.

• Convex Images-Images reflected on convex mirrors appear smaller than they really are--which can be seen in the majority of automobiles. As opposed to concave mirrors, they offer a smaller and wider view.

USES OF THE CONCAVE MIRROR1. to make a microscope2. used in headlights of vehicles to send parallel rays to infinity3. shaving mirror to get an enlarged image of the face4. used by dentist’s to see a bigger image of the tooth/teeth

5. used in solar powered projects where they reflect the heat rays of the sun so that they are concentrated at one place.6. magnifying mirror7. make-up mirror8. telescopes

USES OF CONVEX MIRROR1. view finder in vehicles because it reflects a wider image area.2. used in supermarkets and stores for surveillance3. making sunglasses lenses and telescopes.

Lenses helps reflect some of the sunlight some of the sunlight away from the eyes.4. magnifying glass5. used as home decor

Structure of the human eye

Converging lens and Diverging lens

Basic Types of lenses

1. the convex lens (orconverging lens) 2. the concave lens (or diverging lens).

• Due to refraction, light rays bend as they pass into and out of the lens

• Convex lenses are shaped so that the rays converge together;

• concave lenses are shaped to spread rays apart.

Eye lens anatomy