Collision between electron and H atom

[utkarshakash]

Homework Statement

An electron with KE 5eV is incident on a H atom in its ground state. The collision
A)must be elastic
b)may be partially elastic
c)must be completely inelastic
d)may be completely inelastic

More than one option may be correct

Homework Equations

The Attempt at a Solution

In ground state energy of H atom is -13.6eV. Now the question remains if an electron collides does its KE remains conserved?

 

[ShayanJ]

The energy of the first excited state of the hydrogen is 3.4 eV so the difference becomes 10.2 eV which is larger than 5eV so the collision must be elastic.