COMEDK · Physics · 28. Atomic Physics

An atom has a single electron. Its ground state energy is \(-30\ eV\) and its first excited state energy is \(-8\ eV\). The atom is bombarded with a stream of photons, each of energy \(15\ eV\). Assuming the atom being in the ground state, which of the following statements is correct?

A Atom gets excited to the first excited state and later emit photons of \(22\ eV\)
B Atom absorbs energy continuously until \(22\ eV\) is accumulated and then gets excited
C Atom will not get excited, and the transmitted light will have the same frequency as the incident light
D Atom will absorb the photon and re-emit a photon of lower energy

Verified Solution

Answer & Solution

Correct Answer

(C) Atom will not get excited, and the transmitted light will have the same frequency as the incident light

Step-by-step Solution

Detailed explanation

The energy of the atom in the ground state is \(E_1 = -30\ eV\). The energy of the atom in the first excited state is \(E_2 = -8\ eV\). The minimum energy required to excite the atom from the ground state to the first excited state is…

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

No.	Column I	No.	Column II
A	Radiowaves	P	\(10^{18}\) to \(10^{20}\) Hz
B	Microwaves	Q	\(10^{11}\) to \(5 \times 10^{14}\) Hz
C	Infrared	R	\(10^{4}\) to \(10^{8}\) Hz
D	X-rays	S	\(10^{9}\) to \(10^{12}\) Hz

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