Slides in this set

Slide 1

Preview of page 1

Physics P3
Topic 1 through to Topic 5…read more

Slide 2

Preview of page 2

Topic 1- Radiation in treatment
and medicine
Diagnosis methods:
Endoscopes, which use visible light
CAT scans, which use xrays
Ultrasound, which use sound waves
Treatment methods:
Ionising radiation, usually in the form of gamma
rays and xrays
Non-ionising radiation in the form of light (lasers)
and ultrasound…read more

Slide 3

Preview of page 3

Topic 1 Continued
Radiation is energy carried by waves or
particles from a source
The intensity of radiation will decrease with
distance from a source according to the
nature of the medium through which it is
This is calculated through the equation:
intensity=power of incident radiation/area…read more

Slide 4

Preview of page 4

Topic 1 Continued
Light is focused on the retina by the actions of the
cornea and the lens.
The average adult human eye has a near point of
about 25cm and a far point of infinity.
Long sighted people can focus on distant objects
but not near ones. It is caused by the eyeball being
too short and therefore is fixed with a converging
Short sighted people can focus on close objects but
not far ones. It is caused by the eyeball being too
long and therefore is fixed with a diverging lens.…read more

Slide 5

Preview of page 5

Topic 1 Continued
Contact lenses are also available to correct
vision- although they can cause infection
and irritation to the eyes.
Laser correction is also an option where a
laser is used to permanently alter the shape
of the cornea to make it act as a
converging/diverging lens dependant on the
patients requirements…read more

Slide 6

Preview of page 6

Topic 1 Continued
Here we have This is refraction. This This is total internal
reflection. occurs because the reflection, this occurs
light ray slows as it when the angle of
Snell's law explains enters the glass due to incidence is greater
refraction: the density. It therefore than the critical angle.
bends towards the
Sin i/sin r = nr/ni normal. To calculate the critical
(with n being the refractive angle:
index) Sin C=1/n
(n being the refractive
index)…read more

Slide 7

Preview of page 7
Preview of page 7

Slide 8

Preview of page 8
Preview of page 8

Slide 9

Preview of page 9
Preview of page 9

Slide 10

Preview of page 10
Preview of page 10


No comments have yet been made

Similar Physics resources:

See all Physics resources »