Matter and radiation

Question 1

what is the relative charge and mass of a proton?

Answer 1

+1 and 1

Question 2

What is relative charge and mass of a neutron?

Answer 2

0 and 1

Question 3

What is the relative charge and mass of an electron

Answer 3

-1 and 1/1840

Question 4

How are electrons held in the nucleus?

Answer 4

By electrostatic forces of attraction between the nucleus

Question 5

Definition of an isotope?

Answer 5

Atoms with same number of protons but with a different number of neutrons

Question 6

What is A and Z for an element

Answer 6

A is the nucleon number and (Total proton and nuetron number) Z is the proton number

Question 7

What is the specific charge of a charged particle?

Answer 7

Charge divided by mass

Question 8

Which sub atomic particle has the highest specific charge?

Answer 8

The electron

Question 9

What is the force that keeps protons and neutrons together?

Answer 9

Strong nuclear force

Question 10

What is the range of the strong nuclear force. When is it an attractive force and when is it a repulsive force?

Answer 10

Range no more than 3-4 fentometers. Attractive force from 3-4 fm down to about 0.5 fm. Repulsive force with separations smaller than this, to prevent neutrons and protons from being pushed into each other.

Question 11

What is released in alpha radiation?

Answer 11

An alpha particle, also called a helium particle, of mass 4 and proton number 2.

Question 12

What is released in beta radiation? When does beta radiation occur?

Answer 12

A beta particle is released. Of mass number zero and charge of -1. It occurs when a neutron in the nucleus changes into a proton.

Question 13

What else is released in beta radiation as well as a beta particle?

Answer 13

An antineutrino.

Question 14

Why was existence of antineutrino hypothesised?

Answer 14

To account for conservation of energy in beta decay

Question 15

What is a photon? What is it’s energy equal to?

Answer 15

A burst of a packet of E.M waves. E=HF, where frequency = c/wavelength

Question 16

What are three properties which apply to all antiparticles?

Answer 16

They annihilate their corresponding particle if they meet, converting total mass into photons. They have exactly the same rest mass their particle, and also the opposite charge to the particle, if the particle is charged.

Question 17

What is 1 E.V equal to ?

Answer 17

1.6 times ten the power of minus 19 Joules.

Question 18

When does annihilation occur?

Answer 18

when particle and corresponding antiparticle meet, and convert their mass energy into radiation energy.

Question 19

What is produced in annihilation?

Answer 19

2 photons. Minimum energy of each photon produced is E0, which is the rest energy of the particle.

Question 20

When does pair production occur?

Answer 20

When a photon with sufficient energy passes near a nucleus/electron, it can suddenly change into a particle - antiparticle pair.

Question 21

What is minimum energy of photon needed?

Answer 21

HFmin = 2E0, so a photon with less energy than this could not create a particle - antiparticle pair.

Question 22

E.M force between 2 charge particles is due to the exchange of what?

Answer 22

Virtual photons. They are virtual because we can’t detect them directly. They are the exchange particle of the electromagnetic force.

Question 23

What does an exchange particle transfer?

Answer 23

Force, energy and momentum. Sometimes charge

Question 24

What are the 4 fundamental forces and what is their order of strengths, from strongest to weakest.

Answer 24

Strong nuclear force, electromagnetic force, weak nuclear force and gravity.

Question 25

Which exchange particle is associated with the weak nuclear force?

Answer 25

w+ and w- boson. Weak interaction is limited to beta plus and beta minus decay, electron capture, and electron - proton collisions

Question 26

Which exchange particle is associated with the strong nuclear force?

Answer 26

The gluon