Medical Physics Flashcards

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1
Q

What is sound?

A

A form of energy transferred as a wave through solids, liquids, and gases.

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2
Q

How fast does sound travel?

A

Sound travels at 340 metres per second in air.

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3
Q

What causes sound?

A

Sound is caused by vibrations.

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4
Q

What is the number of vibrations in 1 second called and what it is measured in?

A

Number of vibrations in one second is called the frequency of the sound. It is measured in
hertz (Hz).

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5
Q

What frequency do high-pitch and low-pitch sounds have?

A

High pitched sounds have high frequency. Low pitched sounds have low frequency.

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6
Q

What can humans hear up to?

A

Between 20Hz to 20,000Hz

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7
Q

?? dB damages hearing

A

?? - 90 dB

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8
Q

Changing the frequency of a sound changes the what?

A

the pitch

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9
Q

Higher amplitude of a sound looks like?

A

waves with a greater amplitude (they are taller)

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10
Q

Higher frequency of a sound looks like?

A

More waves

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11
Q

What is ultrasound?

A

Vibrations above 20,000Hz are called an ultrasound.

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12
Q

What can an ultrasound be used for?

A

Breaking up kidney stones, create images of inside body and can detect blood flow.

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13
Q

How does an ultrasound work?

A

they bounce off different parts of the body, they create “echoes” that are picked up by the probe and turned into a moving image.

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14
Q

What is sound level measured in?

A

Decibels (dB)

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15
Q

What is light?

A

A form of energy transferred as a wave.

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16
Q

How fast does light travel?

A

Light travels at 300 million metres per second.

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17
Q

What can light pass through?

A

A vaccuum

18
Q

What direction does light travel in?

A

Light travels in straight lines. Direction only changes if it is reflected or refracted.

19
Q

What are the 2 types of lenses? and how do they work?

A

Lenses work due to refraction.
Convex lenses cause light to converge (come together). Concave lenses cause light to diverge (move apart).

20
Q

Main parts of the eye:

A

cornea; pupil; iris; lens; retina; and optic nerve.

21
Q

The eye does what to light?

A

Eye converts light to electrical signals interpreted by the brain.

22
Q

What do long sighted people see and what corrects it?

A

Long-sighted people can see distant objects clearly but close objects are blurred. Corrected by convex lens.

23
Q

What do short sighted people see and what corrects it?

A

Short-sighted people can see close objects clearly but distant objects are blurred. Corrected by concave lens.

24
Q

What is white light made up of?

A

different colours – ROYGBIV the rainbow
spectrum.

25
Q

What are laser beams?

A

LASER beams are very narrow beams of light energy of a single
colour.

26
Q

What is the EM spectrum?

A

Family of waves similar to light but invisible to human eyes.

27
Q

What is on the EM spectrum?

A

● TV/Radio
● Microwave
● Infrared (IR)
● Visible light
● Ultraviolet (UV)
● X-rays
● Gamma rays

28
Q

Order of lowest frequency to highest:

A
  1. Radio Waves
  2. Microwaves
  3. Infrared Waves,
  4. Visible Light Rays,
  5. Ultraviolet,
  6. X-rays
  7. Gamma Rays.
29
Q

What is infrared?

A

heat energy

30
Q

what can infrared energy be used for?

A

In medicine, thermograms can be used to diagnose many conditions and detecting fake bank notes

31
Q

What is Ultraviolet light?

A

Ultraviolet energy is produced naturally by the Sun.

32
Q

What happens if you’re exposed to too much UV?

A

Too much ultraviolet exposure can cause skin damage.
Large doses of ultraviolet energy can increase our risk of serious conditions like skin cancer

33
Q

How can you protect yourself from the sun?

A

Stay in the shadows, or use sun cream.

34
Q

What are X-rays?

A

X-ray radiation, is a high-energy electromagnetic radiation

35
Q

What can X-rays be used for?

A

In medicine X-rays can be used to diagnose many conditions

36
Q

How do x-rays work?

A

The X-rays pass through the body and are absorbed in varying amounts

37
Q

What do things show up as on X-rays?

A

Denser material absorbs more X-rays than less dense material
Bone appears as white on an X-ray image, whilst lungs with air in them appear as black. Muscle and fat show up as different shades of grey

38
Q

What are gamma rays?

A

Penetrating electromagnetic radiation of a kind arising from the radioactive decay of atomic nuclei.

39
Q

What can gamma rays be used for?

A

In the medical field, gamma rays are used in cancer screening devices and in surgical procedures to guide removal of tumors.

40
Q

How do gamma rays work?

A

Gamma radiation is highly penetrating and interacts with matter through ionisation via three processes; photoelectric effect, Compton scattering or pair production