Radioactivity

Question 1

Who made the plum pudding model

Answer 1

Jj Thompson

Question 2

What did earnest Rutherford discover
Give three conclusion

Answer 2

Most of the atom was empty space
The nucleus was positive
The nucleus must be very small and very dense

Question 3

What is the modern day accepted model of a nucleus

Answer 3

Rutherford Bohr model

Question 4

What is the definition of radioactivity

Answer 4

The disintegration of unstable nuclei by emitting alpha beta or gamma particles spontaneously and randomly

Question 5

Describe an alpha particle

Answer 5

Is equivalent to a helium nucleus
Is a particle
Is emitted from the nucleus
Has a charge of +2
And has a mass of 4x a neutron
Can be stopped by 2-3cm of paper

Question 6

Describe a beta particle

Answer 6

Is equivalent to a high speed electron
Is a particle
Is emitted from the nucleus
Has a charge of -1
Has a mass of 1/1840xneutron
Can be stopped by aluminium

Question 7

Describe a gamma wave

Answer 7

Is a high energy em wave
Is emitted from the nucleus
Has a charge and mass of 0
Can be stopped by lead

Question 8

What is background radioactivity

Answer 8

When radioactivity is detected when no active source is present

Question 9

Give the five main sources of background radiation

Answer 9

Gas from the ground
Cosmic rays
Rocks
Human body and food
Artificial sources

Question 10

Give 3 precautions when working with a radioactive source

Answer 10

Long tweezers
Minimise exposure
Maintain a 2 metre distance