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Flashcards in Half Lives Deck (18):
1

What does a Geiger counter measure?

The radiation (photons or particles) emitted per second

2

What is the unit for measuring radiation?

Becquerels (Bq)

1 Bq = 1 count (wave or particle) per second

3

What is Half-life?

The time it takes for half the unstable nuclei to decay or for the activity to halve

4

What happens to atoms that decay?

They don't disappear, they change to the atom of a different element and eventually become stable

5

What will the half-lives of different isotopes of an element be?

Different

6

What is net decline?

the ratio of the final to intial activity eg. after one half life the ratio will be 1:2, then after 2 it will be 1:4

7

What is a photon model?

In a photon model, electromagnetic radiation is emitted and absorbed as packets of energy called photons

8

What is the energy of each photon proportional to?

The frequency

9

What does an absorption spectrum show?

a set of frequencies of radiation absorbed by an atom when exited electrons move to higher energy levels

10

What can a photon that has enough energy do?

Completely remove and electron from the atom, the atom is ionised

11

Photons of what frequencies have enough energy to ionise atoms?

Ultraviolet, X-ray, Gamma ray frequencies

12

What does an emission spectrum show?

A set of frequencies of radiation emitted by an atom when exited electrons move to lower energy levels

13

What does the frequency of radiation emitted depend on?

The difference in energy of the energy levels

14

What happens if there are more than one energy changes?

If there are two changes then the emitted photons have less energy, lower frequencies and longer wavelengths

15

What is the largest energy difference from?

An energy level just below ionisation

16

What are the highest energy photons from?

A hydrogen atom in the ultraviolet part of the electromagnetic spectrum

17

What is a photon?

A 'packet' of electromagnetic radiation, how radiation is emitted or absorbed

18

What type of rays are the highest energy radiation?

Gamma