Physics 3 - Physics in Medicine

HideShow resource information
  • Created by: Alice
  • Created on: 07-04-15 18:18

X-Rays

X-Rays are electromagnetic waves with a short wavelenth.
They are ionising, so potentially dangerous.

1 of 16

Ultrasound

Ultrasound waves are sound waves with a frequency above 20,000 Hz.
Ultrasound reflects off boundaries between materials.

2 of 16

Refraction

Refraction is the bending of light when it moves from one medium to another.
Lenses use refraction to form an image.

3 of 16

Refractive index

Refractive index is a measure of the speed of light through a material compared with the speed of light in a vacuum.

4 of 16

Images

The nature of an image is determined by its distance from the lens, its size, its orientation, and wheter it is real or virtual.

5 of 16

Converging Lense

The image produced by converging lenses is real and inverted, or virtual, upright and magnified.

6 of 16

Diverging Lense

The image produced by diverging lenses is virtual, upright, and diminished.

7 of 16

Magnification

Magnification = image height/object height

8 of 16

Human Eye

The human eye has a range of vision from 25cm to infinity.
Features of the eye:  retina; cornea; iris; pupil; ciliary muscles; suspensory ligaments.

9 of 16

Short-sight

Short-sight is inability to focus on far away objects.
Corrected by diverging lenses.

10 of 16

Long-sight

Long-sight is inability to focus on near objects.
Corrected by converging lenses.

11 of 16

Camera

In a camera a converging lens focuses light onto photographic film or a charge-coupled device (CCD) to produce a real image.

12 of 16

Powerful lenses

More powerful lenses have shorter focal lengths.
Lens power is measures in dioptres.
Power = 1/focal lenght.

13 of 16

TIR

If the angle of light travelling from a denser medium towards a less dense medium exceeds the critical angle, total internal reflection (TIR) occurs.

14 of 16

Optical fibres

Optical fibres channel light through total internal reflection, and are used for communication and in endoscopes.

15 of 16

Lasers

Laser beams remain very narrow even over long distances.
Their intensity means they can be used to cut, etch, or cauterise objects - including in laser eye surgery.

16 of 16

Comments

No comments have yet been made

Similar Physics resources:

See all Physics resources »See all Medical Physics resources »