3.8 Nuclear Physics

Question 1

Define Rutherford’s Experiment

Answer 1

Fired alpha particles at a very thin gold sheet.
They mostly passed through but some were deflected at large angles.
This disproved the ‘plum pudding’ model.
The deflections were caused by the electrostatic repulsion between the moisture nucleus and positive alpha particles.
Most passed through proving atoms are mostly free space.

Question 2

What are alpha particles?

Answer 2

Two protons and two neutrons (the equivalent of a helium nucleus).
Weakly penetrating.
Highly ionising.
Easily absorbed.
Positively charged.