A nucleus of the stable isotope Pb(208,82) has more neutrons than protons. Explain why there is this imbalance between proton and neutron numbers by referring to the forces that operate within the nucleus.

Must include 3 points from 1-5 and 1 point from 6-7 for 4 marks.1.Strong nuclear force (SNF) affects nucleons or protons and neutrons.2. SNF attraction extends up to 3 fm (allow 1–4 fm) 3. The SNF is repulsive below about 0.8 fm (allow 0.3 to 1 fm and prevents the nucleus totally collapsing) 4. Electromagnetic/electrostatic repulsive force (only) acts between protons 5. EM forces are long range/infinite/acts across whole nucleus/acts on all protons(so increases as proton number increases)6. More neutrons are needed to hold nucleus together / add to binding force/increase instability/reduce stability 7. Fewer protons are required so as to reduce the repulsion/reduce instability/increase stabilityProcess of answering:

Related Physics A Level answers

All answers ▸

A ball is thrown in the air with velocity of 50.0 m/s, assuming no air resistance calculate its maximum height.


The mercury atoms in a fluorescent tube are excited and then emit photons in the ultraviolet region of the elecrtomagnetic spectrum. Explain how the mercury atoms become excited.


In a particle accelerator, you accelerate an electron. Afterwards, you measure it's energy to be 350 keV. Tell my why you can't find the speed from this energy using your knowledge of classical mechanics.


How would you calculate the moment of a Force on a rigid object?