STP Waves and Rad 213 cards

Tagged as: economics, communications, nursing, physics, chemistry

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1

How are UV waves used?

Sun beds, invisible ink, security coding.

2

Give uses of infra red.

Heaters, optical fibres, remote controls.

3

Give uses of microwaves.

Communications (e.g. to satellites), heating food (it heats from inside out heating water molecules).

4

Gives uses of radio waves.

Communications, longer waves can reflect off part of the atmosphere (the ionosphere).

5

What is the advantage of optic fibres carrying infra red and visible light?

They can carry much more info (shorter wavelengths carry more). Also due to total reflection all the info stays in the fibre so it is more secure.


7

What is the difference between analogue and digital signals?

Analogue is a continuous wave. It can suffer a lot of interference. Digital is a sequence of pulses (either 1 or 0). They suffer less from interference and the signal can be easily 'cleaned' by a regenerator. Examples are e-mail, mobile phones, modern TV's.

8

Complete the equation: Wave speed = ? (m/s)

Frequency x wavelength (hertz, Hz) (metres, m)

9

What is the basic structure of an atom?

A small central nucleus containing protons and neutrons surrounded by electrons.


11

What are isoptopes?

Atoms with same of protons but different numbers of neutrons.


13

What are the three types of radiation called?

Alpha (α) (a helium nucleus), beta (β) (a high energy electron) and gamma (γ) 9high frequency EM radiation).