`A` hydrogen-like atom has ground state binding energy `122.4eV`. Then :

Options

A. its atomic number is `3`
B. an electron of `90 eV` can excite it to a higher state
C. an `80 eV` electron cannot excite it to a higher state
D. an electron of `8.2 eV` and a photon of `91.8 eV` are emitted when a `100 eV` electron interacts with it

Answer

A, C, D

Explanation

`Delta x = 2Deltap" "Deltax .2Deltap = (h)/(4pi)`
`2(Deltap)^(2)=(h)/(4pi)" "(Deltav)^(2)=(h)/(8pim^(2))`
`Deltav=(1)/(2m)sqrt((h)/(2pi))" "Deltav=(1)/(2m)sqrt(h)`