Electromagnetic Radiation

Question 1

Describe properties and uses of ultraviolet

Answer 1

• Higher frequency than violet light
• body needs exposure to ultra violet rays to absorb vitamin D.
• can amuse a material to fluoresce if hit (absorb UV light and emit visible light. This makes objects appear brighter.

Question 2

Properties of X-rays.

Answer 2

Have penetrating powers so are used to investigate structures of objects to find flaws in metals.

• can also damage cells
• used in radiology to produce images of bones
• used in radiotherapy to kill cancer cells or stop them from multiplying.

Question 3

Gamma rays

Answer 3

• high energy
• very small wavelengths.
• produced in making nuclear power/bombs.
• can be detected by photographic film or a machine called a Geiger counter.
• can ionise atoms which can be used in radiotherapy to kill cancer cells in patients

Question 4

Define wavelength

Answer 4

Distance between two successive waves.

Question 5

Define amplitude

Answer 5

Maximum distance it extends beyond its middle position.

The larger the amplitude the more energy it has.

Question 6

Define frequency

Answer 6

Number of waves per second.

Question 7

Describe the electromagnetic spectrum and compare wavelengths.

Answer 7

The entire range of frequencies.
In order from lowest to highest.
Radio-microwaves-infrared-visible-UV-X-rays-gamma
Higher the frequency, shorter the wavelength, the more energy is carried by the radiation.

Question 8

Explain how lights are coloured by the light reflected. Identify primary colours as red, green and blue.

Answer 8

If you were to shine a red light on a candle that looked white under white light it appears red as the candle absorbs everything but the colour of light being reflected.

Question 9

Understand that primary colours combine to form white light and secondary colours are formed by combinations of two or more primary colours.

Answer 9

Using all three primary colours produces white light.
Secondary colours are combinations of primary colours.
These are;
-magenta
-cyan
-Yellow

Primary colours are;
Red, green and blue.

Question 10

Describe microwaves and their use

Answer 10

Microwaves have shorter wavelengths than radio waves

• used in radar and communication systems
• absorb water, fats and sugars in foods causing molecules to vibrate then heat up.

Question 11

Identify that snakes use infrared radiation at night

Answer 11

Prey emit infrared radiation and snakes can detect this from warm bodies one metre away.