###### A-Level Notes > Manchester High School For Girls Sixth Form A-Level Notes > Physics AS Level Notes

This is a sample of our (approximately) 4 page long Matter And Radiation notes, which we sell as part of the Physics AS Level Notes collection, a A package written at Manchester High School For Girls Sixth Form in 2013 that contains (approximately) 36 pages of notes across 13 different documents.

The following is a plain text extract of the PDF sample above, taken from our Physics AS Level Notes. This text version has had its formatting removed so pay attention to its contents alone rather than its presentation. The version you download will have its original formatting intact and so will be much prettier to look at.

Unit 1: 1 Matter and Radiation

INSIDE THE ATOM

-Rutherford's alpha-particle scattering experiment discovered a nucleus of protons and neutrons, orbited by electrons. Proton Number (Z)

A Z

X

Number of protons in the nucleus

Nucleon Number (A)

Number of nucleons in the nucleus (protons and neutrons)

ISOTOPES - same number of protons but different number of neutrons. RELATIVE ATOMIC MASS:

mass of atom one twelfth the mass of a 126C atom

CHARGE-TO-MASS RATIO (SPECIFIC CHARGE)/C kg-1:

total charge on particle(C) mass of particle (kg)

NB: the electron has the largest speciﬁc charge of any particle (due to very small mass).

FUNDAMENTAL FORCES Fundamental Force

Responsible for

Relative Strength

GRAVITATIONAL

Weight, gravitational attraction

10-38

ELECTROMAGNETIC

Friction, normal reaction, upthrust etc.

10-2

WEAK NUCLEAR

10-5

STRONG NUCLEAR

Holding nuclei together

1

Due to the gravitational force being so weak, it is considered to be negligible in particle Physics.

The role of the strong nuclear force

-The strong nuclear force overcomes the mutual electrostatic forces of repulsion between the protons in a nucleus as well as preventing the neutrons from decaying.
-The force varies with distance and only works on an extremely short range (attractive up to 3x10-15m and repulsive below 0.5x10-15m). These ranges explain why it holds the nucleons together in the nucleus but they do not collapse in on each other.

PHYSICS AS NOTES

1

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