NUST NET Physics — Atomic Spectra
Atomic Spectra is part of the FSc Physics course that NUST NET-Engineering draws on (Physics is 60 of the 200 MCQs). It breaks into 2 subtopics, and we hold 45 NET-pattern practice MCQs on it, each with a written explanation. Tap a subtopic below to practise just that.
Subtopics (2)
How Atomic Spectra is tested
Across the 8 NET-pattern papers on ParhaiKrlo, Atomic Spectra accounts for 18 questions. It appears in all 8, about 2.3 questions a paper. The heaviest was NUST NET Past Paper 04, with 3 questions, and the most recent is NUST NET Past Paper 07, with 2.
| Paper | Questions |
|---|---|
| NUST NET Past Paper 07 | 2 |
| NUST NET Past Paper 08 | 2 |
| NUST NET Past Paper 05 | 2 |
| NUST NET Past Paper 06 | 2 |
| NUST NET Past Paper 03 | 2 |
| NUST NET Past Paper 04 | 3 |
| NUST NET Past Paper 01 | 3 |
| NUST NET Past Paper 02 | 2 |
Atomic Spectra MCQs from the NET-pattern papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · NUST NET Past Paper 07 · Atomic Spectra
The energy needed to ionize a hydrogen atom whose electron is in the n = 2 level is:
- A.13.6 eV
- B.3.4 eV
- C.10.2 eV
- D.1.51 eV
Show answer
Answer: B. 3.4 eV — Eₙ = −13.6/n² eV; at n = 2, E = −3.4 eV, so 3.4 eV ionizes it.
- Q2 · NUST NET Past Paper 08 · Atomic Spectra
The energy of the electron in the n = 3 orbit of a hydrogen atom is:
- A.−4.53 eV
- B.−3.4 eV
- C.−1.51 eV
- D.−0.85 eV
Show answer
Answer: C. −1.51 eV — Eₙ = −13.6/n² = −13.6/9 ≈ −1.51 eV.
- Q3 · NUST NET Past Paper 05 · Atomic Spectra
The radius of the first Bohr orbit of hydrogen is 0.053 nm. The radius of the third orbit is:
- A.0.477 nm
- B.0.159 nm
- C.0.053 nm
- D.0.212 nm
Show answer
Answer: A. 0.477 nm — rₙ = n²r₁ = 9 × 0.053 = 0.477 nm.