physics optics

what is light

light is a form of energy that travels away from the source producing it at the speed of lightof 3×10^8

what is reflection

the bouncing of light from the surface of an object

laws of reflection of light

1. the incident ray ,normal at the point of incidence and reflected ray all lie in the same plane

2. the angle of incidence is equal to the angle of reflection

what is a virtual image

an image formed by the apparent intersection of rays. it cannot be formed on a screen

what is parallax

the apparent movement of one object relative to another due to the motion of the observer

what is lateral inversion

the image of an object will appear flipped in a plane mirror

what is a real image

the actual intersection of rays. it can be formed on a screen.

what is a concave mirror 

a mirror which caves in at the centre

what is a convex mirror

a mirror that bulges out at the centre

what is refraction

the bending of light when it goes from one medium to another

what are the laws of refraction of light

1. the incident ray , the normal at the point of incidence and the refracted ray all lie in the same plane

2. the ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant

what is the refractive index

the ratio of the sine of the angle of incidence to the sine of the angle of refraction when light travels from air into that material

what is a critical angle

when light travels from a denser to a rarer medium the angle of incidence whose angle of refraction is 90°

what is total internal reflection

when light going from a denser medium to a rarer medium strikes the rarer medium at an angle greater than the critical angle, it does not enter the second medium it is reflected back in the denser medium.

what are the two types of lenses

1. convex / converging lens 

2. concave / diverging lens

describe the vision of a short sighted person

a short sighted person can see nearby objects clearly but cannot see distant objects clearly

the image falls short of the retina (mytopia)

corrected with a diverging lens

describe the vision of a long sighted person

a long sighted person can see distant objects clearly but cannot see nearby objects clearly

image falls past the retina (hyperopia)

corrected with a converging lens

give one advantage and one disadvantage of using a convex mirror instead of a plane mirror as a wing mirror on a car

adv. wider field of view

disadv. the image is diminished

what type of image does each mirror give (convex/concave)

convex: upright image

concave: inverted image