6.2 Radioactivity

Detecting radioactivity: SPARK COUNTER
> f__ w__ stretched below piece of metal g__
> high v__ put between, enough until almost s__
> w/ t__, put r__ near gauze
> rays from it i__ air = better c__ = s__

fine wire, gauze, voltage, sparking, tweezers, radium, ionise, conductor, spark

Detecting radioactivity: PHOTOGRAPHIC FILM
> r__ will b__ photographic f__ unless smth big covers e.g. x-ray

radioactivity, blacken, film

Detecting radioactivity: Geiger–Müller tube
> m__ tube w/ thin w__ in centre, has g__ at low p__
> like spark counter but less V (no spark), instead c__ made
> amplified & passed to scaler/ratemeter

metal, wire, gas, pressure, current

Nuclear Emissions
> r__ emissions are s__ & r__ in direction
> u__ nucleuses emit r__ to be more s__

radioactive, spontaneous, random, unstable, radiation, stable

⁴₂__ or ^__{_}α
> shown w/ __ nucleus
> __ve charge
> __ ionising
> __ penetration
> stopped by t__ p__/s__

He, 4 2, He, +, high, weak, thin paper, skin

⁰_-1__ or ^__{_}β^-
> shown w/ __-
> __ve charge
> __ ionising
> __ penetration
> stopped by a__

e, 0 -1, e, -, mild, mild, aluminium

γ
> shown w/ γ
> __ charge
> __ ionising
> __ penetration
> stopped by thick l__/c__

0, weak, high, lead, concrete

List the radiations, top to bottom

alpha, beta, gamma

beta has more d__ than alpha bc of s__ m__
gamma has passes s__ thru as it has no c__

deflection, smaller mass, straight, charge

w/ alpha & beta decay, nucleus changes to diff e__

element

α-emissions
> will lose _p & 2_

2, n, 4, 2, 4, 2

β-emissions
> fast moving e- e__ from n__

ejected, nucleus, 1, -1

γ-emissions
> high e__ EM waves
> usually part of alpha/beta decay

energy, 0, 0

Effect of alpha/beta decay on the nucleus
> ↓# of excess n__
> ↑nucleus s__

neutrons, stability

Isotopes can be radioactive bc:
Ø  E__ n__ in nucleus
AND/OR
Ø  Nucleus too h__

excess neutrons, heavy

Half-life

time taken for 1/2 the particles in a sample to decay

Which letter shows 1 half-life

A

Fission reactions
Ø    Large n__ splits → 2 lighter nuclei & e__
> neutrons emitted strike other U nuclei = c__
> f__ reactors use U-235 as f__

nucleus, energy, chain, fission, fuel

Safety precautions
Ø  i__ radiation = m__, burns, cell d__
1.      Store in l__ container
2.      Minimise e__; wear lead s__, etc
3.      Handle w/ long t__

ionising, mutation, death, lead, exposure, shield, tongs