Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Moments and Centre of Mass
· The weight of a pivoted object can have a turning effect. If the pivot passes through its centre of
mass, the object does not turn, clockwise or anticlockwise. If a force is applied at a distance
from the pivot it has a turning effect (moment). A force has a greater turning effect (moment):
a) the greater the size of the force;
b) the greater the perpendicular distance between the line of action of the force and the pivot.…read more

Page 3

Preview of page 3

Here's a taster:

Circular Motion
· When an object moves in a circle at a steady speed, the direction of its motion, and thus its
velocity, is constantly changing. Therefore, from Newton's Second Law of Motion, a force
towards the centre of the circle (a centripetal force) is needed. In the case of a washer being
whirled around on a piece of string, the force comes from the tension in the string.…read more

Page 4

Preview of page 4

Here's a taster:

Reflection
· When a ray of light is reflected from a flat (plane) mirror, or a piece of glass the angle at which
it leaves the surface (angle of reflection) is the same as the angle at which it meets the surface
(angle of incidence).
· Angles are always measured between the normal (a line drawn at right angles to the surface
where the ray strikes) and the ray itself
· Sounds also bounce back (reflect) from hard surfaces and are heard as echoes.…read more

Page 5

Preview of page 5

Here's a taster:

Curved Mirrors
· Curved mirrors work by reflecting light rays according to the rule on page 4; the normal
lines are still at right angles to the surface, but unlike for a plane mirror, are not parallel to
each other
· Curved mirrors are either convex (the back of a spoon) or concave (the inside of a spoon).…read more

Page 6

Preview of page 6

Here's a taster:

Constructing ray diagrams for curved mirrors
1. A clear well-focussed image is formed at a point where two or more rays from the same
point on the object meet up
2. A light ray travelling parallel to the principal axis is reflected by the curved mirror so as to
actually pass through (for a concave mirror) or to appear to have passed through (for a
convex mirror) the principal focus.
3.…read more

Page 7

Preview of page 7

Here's a taster:

Refraction
· Waves are refracted because they travel at different speeds in different substances (media).
· Rays of light change direction (are refracted) when they cross the boundary between one
transparent substance and another, unless they meet the boundary at right angles (along a
normal).
· Sounds, like light, are also refracted, i.e. their direction is may be changed when they cross the
boundary between two different media.
· When rays of light pass through prisms their direction may be changed.…read more

Page 8

Preview of page 8

Here's a taster:

Total Internal Reflection
· When a ray of light travels from glass (or any transparent material ­ Perspex, water,
diamond, etc) into air, some of the light is also reflected from the boundary back into the
material.
· If the angle between the ray and a normal is greater than a certain angle (called the critical
angle), all of the light is reflected back into the glass. This is called total internal reflection.…read more

Page 9

Preview of page 9

Here's a taster:

Lenses
· Lenses work by refracting the light at two boundaries according to the rules on page 7. There
are converging and diverging lenses, which cause parallel rays of light incident upon them to
move together/apart after they pass through.
· You should be able to construct ray diagrams to show the formation of images by lenses using
the following:
1. A clear well-focussed image is formed at a point where two or more rays from the same
point on the object meet up
2.…read more

Page 10

Preview of page 10

Here's a taster:

The Eye
· Light emitted or reflected by an object enters the eye through the transparent cornea, where it
undergoes refraction. Together with the lens, the cornea allows a real inverted image to be
produced on the retina. The retina contains millions of rods and cones, which are sensitive to
light intensity and colour respectively, and sends electrical impulses along the optic nerve to the
brain.…read more

Comments

No comments have yet been made

Similar Physics resources:

See all Physics resources »See all resources »