Particles and nuclides

Question 1

What is an isotope?

Answer 1

each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties.

Question 2

What is the relative charge of a copper atom that has lost two electrons?

Answer 2

+2

Question 3

What is specific charge?

Answer 3

It is the charge per unit mass.

Question 4

What is the equation for specific charge?

Answer 4

Specific charge of a particle = charge of the particle/ mass of the particle.

Question 5

How many protons neutrons and electrons are there in silicon
28
14

Answer 5

14 protons 14 neutrons and 14 electrons

Question 6

What is the specific charge of a deuterium nucleus. (hydrogen 1 proton +1 neutron)?

Answer 6

charge = 1.610^-19
mass = 21.67310^-27 = 3.3810^-27
specific charge = charge/mass = 4.78*10^7 Ckg

Question 7

How do you work out the energy of the photon?

Answer 7

E=hf

Energy of photon = planks constant(6.63x10^-34)*frequency of wave emitted.

Question 8

What are the four fundamental forces?

Answer 8

Strong nuclear force, weak nuclear force, electromagnetic and gravitational

Question 9

What does the strong nuclear force do?

Answer 9

It is the force that acts between nucleons and holds nuclei together and keeps them stable.

Question 10

How large is the strong nuclear force’s attraction?

Answer 10

3fm (femtometre)

Question 11

What is an anti-particle?

Answer 11

It is the particle that has an opposite charge to its original but the same mass. E.g a positron is the anti-particle of the electron.It has the same mass but an opposite charge.

Question 12

What is rest mass-energy?

Answer 12

It is the amount of energy released by converting all of the mass of a particle at rest into energy using the equation E=mc^2

Question 13

What is the mega electron-volts?

Answer 13

The energy of nuclear particles is usually measured in MeV. It is A million times bigger then an electron volt(1.610^-16) it is 1.610^-13.

Question 14

What is annihilation?

Answer 14

It is when a particle and its anti-particle collide and they create two gamma rays moving in opposite directions. The total energy of the gamma photons is equal to the total rest energies of the particles.

Question 15

What is pair production?

Answer 15

This is the opposite process to annihilation. In this process, a photon with enough energy can interact with a large nucleus and be converted directly to a particle anti-particle pair.

Question 16

What is the criteria of pair production.

Answer 16

The photon must have enough energy to create both particles (20.51) = 1.02 MeV or 1.6410^-13

Question 17

How would you calculate the wavelength of a photon?

Answer 17

E=hc/lambda

lambda=hc/E

Question 18

What is the specific charge of a gold 197/79 nucleus. when the mass of the gold nucleus is 3.2910^-25 and the charge on an electron is 1.610^-19?

Answer 18

791.610^-19 = 1.26410^-17
specific charge = (1.26410^-17)/(32.910^-25)
=3.84210^7

Question 19

How do spark counters work?

Answer 19

They work by detecting highly ionising particles. Beta and gamma radiation do not get detected. When the air particles are ionised they produce a spark. The spark jumps across the 5000V gap which makes a sound. It can be counted by sight or hearing it.