Nuclear Physics

Question 1

How can you measure the radius of an atom using alpha scattering?

Answer 1

Measuring the shortest distance between the nucleus and the alpha particle

Question 2

When are alpha particles closets to the nucleus?

Answer 2

When their potential energy and initial kinetic energy are equal

Question 3

What method can you use to measure the radius of an electron and why?

Answer 3

Electron diffraction - Electron waves diffract due to wave-particle duality

Question 4

Describe + draw the diffraction pattern seen when electron waves diffract:

Answer 4

Bright central maximum, containing majority of incident electrons

Question 5

Describe how the maxima intensity changes with the angle of diffraction

Answer 5

As angle increases intensity decreases

Question 6

Describe how nuclear radius changes with nucleon number + draw graph:

Answer 6

Nuclear radius increases with nucleon number

Question 7

How can you create a straight line of nuclear radius against nucleon number? + draw graph

Answer 7

Plot R (nuclear radius) against A^1/3 (nucleon number)

Question 8

Explain how you derive the equation for nuclear density:

Answer 8

• Nucleons are said to have the same mass (m)
• Nucleus with atomic number A had mass. A x m
• Assuming all nuclei are spherical volume = 4/3πR^3

Question 9

Nuclear density is significantly greater than atomic density, suggesting:

Answer 9

• Moss of the atomic mass is in the nucleus
• The nucleus is small compared to the atom
• The atom must contain a lot of empty space