A stationary radium atom decays, emiting an alpha particle. Why is the recoil speed of the nucleus small compared to the alpha particle?
Initially the momentum is zero.
Due to conservation of momentum, the alpha particle and radium nucleus must gain equal but opposite momentum.
The mass of the radium nucleus is greater than the mass of the alpha particle.
Therefore, the alpha particle has a much greater speed after emission than the radium nucleus. (p = mv)
DD
Related Physics A Level answers
All answers ▸What is the general equation for the alpha-decay of a nucleus X, with nucleon number A and proton number Z, into nucleon Y??
Describe and explain the vertical motion of a parachutist which jumps out of an aeroplane at time t=0 and then releases the parachute shortly after reaching terminal velocity at time t=T. (Assume air resistance is not negligible).
People A and B are taking a lift of mass 500 kg which has constant acceleration and the force from the rope that pulls it is 7500 N. The scales where the people stand show a reading of 720 N and 500 N.
If photons are little particles emitted by atoms, where were they before they got emitted?