A slow electron collides with a hydrogen atom that is already in its first excited state. During the collision, the atom returns to its ground state and transfers the released internal energy to the translational motion of the collision products. What is this type of collision called?
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Question

A slow electron collides with a hydrogen atom that is already in its first excited state. During the collision, the atom returns to its ground state and transfers the released internal energy to the translational motion of the collision products. What is this type of collision called?

Options

G1 Physics · Accepted Answer

The first excited state of hydrogen lies 10.2 eV above the ground state. If the excited atom de-excites during a collision without emitting a photon and transfers that internal energy to the translational motion of the collision partners, the total translational kinetic energy after collision can be greater than before collision. This is called a superelastic collision. Correct option: C.