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Physics > P13 > Flashcards

P13 Flashcards

1
Q

What are the seven bands of the electromagnetic spectrum?

A

Radio waves, Microwaves, Infrared, Visible light, ultraviolet, X- rays, Gamma rays.

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2
Q

List the electromagnetic spectrum in order of frequency and energy.

A

Gamma rays, X-rays, Ultraviolet, Visible light, Infrared, Microwaves, Radio waves.

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3
Q

List the electromagnetic spectrum in order of wavelength.

A

Radio waves, Microwaves, Infrared, Visible light, Ultraviolet, X-rays, Gamma rays.

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4
Q

What is the anagram used to show the parts of the electromagnetic spectrum?

A

Roman Men Invented Very Unusual X-Ray Guns.

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5
Q

The electromagnetic ________ is a group of waves that are divided into _____ bands.

A

spectrum

seven

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6
Q

Gamma rays have the ________ wavelength, highest frequency, and ______.

A

shortest

energy

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7
Q

Which one of the electromagnetic spectrum can the human eye detect?

A

The human eye can only detect visible light.

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8
Q

Electromagnetic waves transfer ______ from a ______ to an ________.

A

energy
source
absorber

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9
Q

What is the wave speed equation?

A

Wave speed (metres per second, m/s)= frequency (Hertz, Hz) * Wavelength (λ)

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10
Q

GIve two everyday uses of parts of the electromagnetic spectrum.

A

Microwave ovens- energy is transferred from a microwave source to the food in the oven, heating it.

Radiators- infrared radiation transfers energy from the heater to heat the surroundings.

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11
Q

TRUE OR FALSE…

Electromagnetic waves do not transfer matter.

A

TRUE

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12
Q

What speed do all electromagnetic waves travel at?

A

3.0 *10^8 m/s (300 million m/s) through space or in a vacuum.

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13
Q

What is white light, and why?

A

White light is light from ordinary lamps and from the Sun. This is because it has all the colours of the visible spectrum in it.

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14
Q

List the parts of the light spectrum from the shortest wavelength to the longest wavelength.

A

Red, Orange, Yellow, Green, Blue, Indigo, Violet.

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15
Q

What is the mnemonic used to list the order of the light spectrum from the shortest wavelength to the longest wavelength?

A

Richard Of York Gave Battle In Vain

(Red, Orange, Yellow, Green, Blue, Indigo, Violet).

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16
Q

TRUE OR FALSE…

All objects emit infrared radiation.

A

TRUE

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17
Q

What does infrared radiation do to your skin?

A

Infrared radiation is absorbed by your skin. It can damage, burn, or kill skin cells because it heats up the cells.

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18
Q

What are optical fibres?

A

A thin flexible fibre with a glass core that is used in communication to transport light signals.

19
Q

Why do optical fibres use infrared radiation instead of visible light?

A

Because infrared radiation is absorbed less than visible light in the glass fibre.

20
Q

Give some uses of infrared radiation.

A

Remote control handsets used infrared radiation to send out a sequence of infrared pulses. It is suitable for this as infrared pulses can easily be produced and detected electronically.

They are also used in medicine to detect infrared radiation emitted from hot spots on the body’s surface. These hot areas can mean the tissue underneath is unhealthy.

Also, you can use infrared cameras to see people and animals in the dark.

It also heats up objects quickly so is used in electric heaters to warm up a room.

21
Q

What are the uses of microwaves?

A

Microwaves are used to carry satellite TV programmes and mobile phone calls.

Also, microwaves are used in a microwave oven that heat food faster than ordinary ovens. This is because microwaves can penetrate into food and are absorbed by the water molecules in the food, heating it.

22
Q

Mobile phone radiation is _________ radiation, and is also _____ _____ at near-microwave frequencies.

A

microwave

radio waves

23
Q

Why can microwaves and radio waves be hazardous?

A

Microwaves and radio-waves can be hazardous because they penetrate people’s bodies and can heat the internal parts of the body.

24
Q

What are carrier waves?

A

Carrier waves are the waves that are used to carry any type of signal. They can be radio waves, microwaves, infrared radiation, or visible light.

25
Q

What does the type of wave used to carry a signal depend on? ( give an example)

A

It depends on how much information is in the signal and the distance the signal has to travel.

For example, microwaves are used to carry signals via satellites to distant countries.

26
Q

What does a shorter wavelength mean for the wave?

A

This means that they can carry more information.
They have a shorter range.
They spread out less.

27
Q

What research has been conducted on mobile phone radiation?

A

Some research has been conducted on the harmful nature of mobile phone radiation. This research has lead to the government and health experts recommending children (who have thinner skulls) to have a limited time spent on mobile phones due to their harmful radiation.

28
Q

What are the advantages of using optical fibres for communications instead of microwaves and radio waves?

A

Optical fibres can carry much more information as light has a much shorter wavelength than radio waves, and so can carry many more pulses of waves.

Optical fibres are more secure because the signals stay in the fibre.

29
Q

What effect do ultraviolet waves have on the human eye?

A

Ultraviolet waves are harmful to human eyes and can cause blindness.

30
Q

What effect do ultraviolet waves have on the human skin?

A

Ultraviolet waves are harmful to the human skin. For example, too much UV directly from the sun or from a sunbed can cause sunburn and skin cancer. It can also cause the skin to age prematurely.

31
Q

Give two methods of preventing eye and skin damage from ultraviolet waves.

A

If you stay outdoors in summer, use skin creams to block UV waves and prevent them from reaching your skin.

If you use a sunbed to get a suntan, don’t go over the recommended time. You should also wear special goggles to protect your eyes.

32
Q

What material can stop x-rays and gamma rays?

A

A thick plate made of lead can stop x-rays and gamma rays.

33
Q

How are x-rays produced?

A

X-rays are produced when electrons or other particles moving at high speeds are stopped- X-ray tubes are sued to produce X-rays.

34
Q

How are gamma rays produced?

A

Gamma rays are produced by radioactive substances when unstable nuclei release energy.

35
Q

What wave is more penetrative to a substance: X-rays or Gamma rays?

A

Gamma rays, because they have shorter wavelengths.

36
Q

Give two uses of gamma rays?

A

1.) It kills harmful bacteria. When you expose food to gamma rays then it will kill 99% of disease-carrying organisms, including Salmonella and Clostridium.

When you expose surgical instruments in sealed plastic wrappers to gamma rays then it will kill any bacteria on the instruments. This helps to stop infection spreading in hospitals.

2.) It kills cancer cells. Doctors and medical physicists use gamma-ray therapy to destroy cancerous tumours. A narrow beam of gamma rays from a radioactive source (cobalt-60) is directed at the tumour. The beam is aimed at it from different directions to kill the tumour but not the surrounding tissue.

37
Q

What is ionisation?

A

Ionisation is when x-rays and gamma rays pass through substances knock electrons out of atoms in the substance. Therefore when the substances lose an electron they become positively charged.

38
Q

What are the dangers of ionisation on the human body?

A

If ionisation happens to a living cell, it can damage or kill the cell. For this reason, exposure to too many X-rays or gamma rays is dangerous and can cause cancer. High doses kill living cells, and low doses cause gene mutation and cancerous growth.

39
Q

What is the use of film badges?

A

People who use equipment or substances that produce any form of ionising radiation (e.g X-rays or gamma rays) must wear a film badge.

If the badge shows that it is over-exposed to ionising radiation, its wearer is not allowed to continue working with the equipment for a period of time.

40
Q

Describe the process as to how somebody is x-rayed?

A

When the X-ray tube is switched on, X-rays from the tube pass through the part of the patient’s body under investigation.

X-rays pass through soft tissue, but they are absorbed by bones, teeth, and metal objects that are not too thin. The parts of the film or the detector that the X-rays reach become darker than other parts. So the bones appear lighter than the surrounding tissue, which appears dark.

The radiograph shows a ‘negative image’ of the bones. A hole of a cavity in a tooth shows up as a dark area in the bright image of the tooth.

41
Q

What is a contrast medium and how can it be helpful in medicine?

A

An organ that consists of soft tissue can be filled with a substance called a contrast medium that absorbs X-rays easily. This enables the internal surfaces In the organ to be seen on the radiograph. For example, to obtain a radiograph of the stomach, the patient is given a barium meal before the x-ray machine is used. The barium compound is a good absorber of x-rays.

42
Q

How does the contrast from the x-ray waves on the body get shown to the doctor for diagnosis?

A

A flat-panel detector is a small screen that contains a charge-coupled device (CCD).

The sensors in the CCD convert X-rays to light. The light rays then create electronic signals in the sensors that are sent to a computer, which displays a digital X-ray image.

43
Q

What are the three types of radiation from radioactive substances?

A

Gamma radiation, Alpha radiation and Beta radiation.

44
Q

Are all radiation types dangerous?

A

All the different types of ionising radiation are dangerous are harmful.

Physics (6 decks)

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