neutron hydrogen collision

JEE Advanced Discussion Forum › Modern physics questions › neutron hydrogen collision

multi correct

A neutron collides head on with a stationary hydrogen atom in ground state.Which of the following are correct( take mass of neutron â‰ˆ hydrogen)

A) if kinetic energy of neutron is less than 13.6 eV , collision must be elastic

B) if KE is greater than 20.4, collision may be inelastic

C) for perfectly inelastic collision minimum KE of neutron should be 10.2 eV

whats the concept here?

#Physics #Modern physics

UP 0 DOWN 0 1 2
Post on FacebookPost anonymously?

2 Answers

Swaraj Dalmia ·2012-03-28 10:07:33

In inelastic collisions energy is lost.
Here lost energy,is only taken up by elec to jump to higher orbit.
The max energy that can be absorbed by elec=13.6eV
Min energy=3/4*13.6=10.2eV

Therefore only in cases when energy is less than 10.2eV there will be no loss of energy,hence elastic collisions.

A)wrong
B)true
c)True.Here all the energy will be absorbed.(hence perfectly inelastic).

Conclusions:
1)For perfectly inelastic collisions energy must lie between 10.2 and 13.6 eV.[and must be discrete corresponding to hydrogen]
2)For inelastic collisions energy must be more than 10.2eV.
3)If energy is lower than 10.2eV,collision must be elastic.[note that is energy is more than 10.2 elastic collisions may still occur]