R EFLECTION Plane (flat) mirrors

L IGHT T RAVELS IN S TRAIGHT L INES

H OW LIGHT BEHAVES …. When light passes from one medium to another it may be reflected, refracted or both. Mirror: ALL the light reflects back Water: SOME of the light reflects back

L AW OF R EFLECTION Law of reflection states that the angle of incidence is equal to the angle of reflection. θ i ° = θ r °

D EFINITIONS 1. Incidence Ray : The ray from the source. (it is the ray from the object to the mirror.) 2. Normal : It is an IMAGINARY line drawn perpendicular to the surface. (It bisects the mirror.) 3. Reflected Ray : The ray reflected from the mirror.

REGULAR ( SPECULAR ) AND D IFFUSE REFLECTION Regular or specular reflection Ex: Mirror Diffuse reflection Ex: Piece of Paper

REGULAR ( SPECULAR ) AND D IFFUSE REFLECTION Regular or specular reflection. Diffuse reflection.

E XTEND YOUR THINKING Why is there a strong glare off the pavement after it rains? Why are glossy books sometimes hard to read?

I MAGES Image – where light rays converge Virtual image – rays do not pass through the image. Images that are formed in locations where light does not actually reach. Virtual images are upright. Real image – rays do pass through so the image can be projected on a screen. Real images are inverted.

P LANE MIRROR AND IMAGE FORMATION  Images are formed because light travels in a straight line.  Image is flipped or reversed

R AYS OFF OF A POINT OBJECT.  Your mind traces back the reflected light rays until they meet somewhere behind the mirror.

R AYS OFF OF A POINT OBJECT. Distance mirror to image = distance mirror to object (di = do)

R AYS OFF OF A POINT OBJECT. The image as seen by the eye is:  Because light rays don’t actually meet in plane mirrors, all images produced are virtual

I MAGE OF AN ACTUAL OBJECT. The image as seen by you is This picture shows that you actually need a mirror that is only half your length to be able to see your full image.

P LANE M IRROR Where do you see your image in the mirror?

I MAGES BETWEEN TWO MIRRORS The kaleidoscope lab show that the angle between the mirrors and the number of images are INVERSLY proportional. And the relationship is A=360 º/N Here A is the angle between the mirrors and N is the # of faces.