INTRO

Question 1

Electrons are fundamental particles belonging to a small family of particles called what?

Answer 1

leptons

Question 2

What does light consist of?

Answer 2

light consists of wave packets of electromagnetic radiation called photons

Question 3

What is a photon?

Answer 3

a quantum, or the least amount of electromagnetic radiation

Question 4

How is energy spread out in quantum theory?

Answer 4

theory that energy is in these lumps (quanta) instead of being evenly spread

Question 5

What has this theory about quatlead to?

Answer 5

discovery of energy levels in the atom, light spectra, and wave-particle duality

Question 6

Why do radioactive substances emit radiation?

Answer 6

the nuclei of their atoms are unstable

Question 7

What can happen when the radiation from radioactive substances passes through other substances?

Answer 7

it can ionise them

Question 8

How is alpha radiation stopped?

Answer 8

paper and is strongly ionising

Question 9

How is beta radiation stopped?

Answer 9

2-3 mm of metal and is less ionising than alpha radiation

Question 10

What are the properties of gamma radiation?

Answer 10

very penetrating and is weakly ionising

Question 11

What is the half-life of a substance?

Answer 11

time it takes for the number of atoms that substances to decrease by half