Edexcel A-Level Physics 9PH0
Working as a Physicist
Mechanics
Electric Circuits
Materials
Waves and Particle Nature of Light
Further Mechanics
Electric and Magnetic Fields
Nuclear and Particle Physics
Thermodynamics
Space
Nuclear Radiation
Gravitational Fields
Oscillations
Nuclear Radiation
Mass deficit, binding energy and the atomic mass unit
- 2 things to know
- Papers 2 and 3
Overview
Recall questions on binding energy and mass deficit, why a nucleus is lighter than its nucleons, ΔE = c²Δm, and the atomic mass unit in SI units, joules and MeV.
What you need to know
Answer each one before you reveal it.
What is the atomic mass unit in SI units, and how is binding energy per nucleon calculated for helium-4?
Questions from this subtopic
Each one with the model answer underneath.
- 1
What is meant by the binding energy of a nucleus?
Model answer
It is the energy that must be supplied to separate a nucleus completely into its individual protons and neutrons.
- 2
What is the mass deficit of a nucleus?
Model answer
It is the difference between the total mass of the separate nucleons and the mass of the assembled nucleus.
- 3
Why is a nucleus always less massive than the nucleons it is made from?
Model answer
Energy is released when the nucleons bind together, and that release of energy corresponds to a loss of mass through ΔE = c²Δm.
- 4
State the equation linking a change in energy to the associated change in mass:
Model answer
ΔE = c²Δm, where c is the speed of light in a vacuum.
- 5
What value of the speed of light should be used in mass–energy calculations?
Model answer
The speed of light in a vacuum is 3.00 × 10⁸ m s⁻¹.
- 6
How is the atomic mass unit defined?
Model answer
One atomic mass unit is one twelfth of the mass of a neutral atom of carbon-12.
Other ways to work this
The same content, four other ways.
What is inside Levo
Six ways to work the same material.
Every question in Nuclear Radiation, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
Or £46 a year, about £3.83 a month. Cancel anytime.