Question

Single electron in an atom has an energy of 40 eV in ground state and energy of 10 eV in the first excited state. A stream of photons with energy of 15 eV strikes the atom. Which of the following transitions is possible?

• A. Electron absorbs the energy, becomes halfway excited and returns to the ground state.
• B. Electron absorbs the energy of one photon, excites to the first excited state and returns to the ground state emitting a 15 eV photon.
• C. The electron absorbs two photons and gets excited to the first excited state.
• D. The electron absorbs multiple photons and leaves the atom.
• E. Nothing will happen

Answer 1

The correct option is E Nothing will happen

The electron needs a minimum of $-10eV-(-40eV)=30eV$ to excite the electron to first excited state.

Hence when photons of energy lesser than the calculated energy strikes the atom, the atom remains unchanged.