Grade 12 Physical Sciences · Matter and Materials

Explain emission and absorption spectra

Explain how bright or dark lines in a spectrum form when electrons jump between energy levels in atoms (the coloured lines of hydrogen).

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Emission & Absorption Spectra Explained | Grade 12 Physical SciencesDanike Aucamp_Wiskunde en Wetenskap

Emission and Absorption SpectraBozeman Science

3 Gr 12 Physical Science - The Photoelectric Effect - Atomic SpectraJuniorTukkie at the University of Pretoria

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Question 1.10 · May/June 2024 · Paper 1 · National (DBE) · 2 marks

Various options are provided as possible answers to the following questions. Each question has only ONE correct answer. Choose the answer and write only the letter (A–D) next to the question numbers (1.1 to 1.10).

1.10 Which ONE of the following combinations is CORRECT for a line absorption spectrum in terms of the ENERGY TRANSITIONS OF THE ATOMS and the APPEARANCE OF THE NARROW LINES IN THE SPECTRUM?(2)

A Energy transition of the atoms: Higher to lower energy state; Appearance of the narrow lines: Dark lines
B Energy transition of the atoms: Lower to higher energy state; Appearance of the narrow lines: Coloured lines
C Energy transition of the atoms: Lower to higher energy state; Appearance of the narrow lines: Dark lines
D Energy transition of the atoms: Higher to lower energy state; Appearance of the narrow lines: Coloured lines

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More past paper questions: explain emission and absorption spectra

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3. Question 10.2.2 · November 2025 · Paper 1 · National (DBE) · 2 marks
10.2 The energy diagram below (NOT drawn to scale) shows the electron energies in different energy levels, $E_{1}$ , $E_{2}$ and $E_{3}$ , of a certain atom.

Answer the questions that follow.
10.2.2 Is it possible for a photon with an energy of $2, 5 \times 1 0^{- 19}$ J to be emitted from this atom? Choose from YES or NO. Give a reason for the answer.(2)
Show the memo (2 ticks)Memo
1. ✓
  ChoiceNo
  1 mark · Explain emission and absorption spectra
2. ✓
  ReasonThe energy does not correspond to any transition in this atom.
  1 mark · Explain emission and absorption spectra
4. Question 10.3.2 · November 2024 · Paper 1 · National (DBE) · 2 marks
10.3 Some of the atoms of a hot gas, made up of a single element, are in an excited state. The spectrum formed by the hot gas is observed on a screen in a darkened room. The spectrum consists of specific coloured lines on a black background.

Answer the questions that follow.
10.3.2 Explain the presence of the coloured lines in the spectrum.(2)
Show the memo (2 ticks)Memo
1. ✓
  What the lines areColoured lines represent (associated) frequencies/wavelengths/energy of the emitted (photons)
  1 mark · Explain emission and absorption spectra
2. ✓
  Where they come fromwhen atoms / electrons move to a lower energy level
  1 mark · Explain emission and absorption spectra
5. Question 10.2.3 · November 2023 · Paper 1 · National (DBE) · 2 marks
10.2 A beam of white light is shone through a cold gas. The emerging light is dispersed and a line spectrum is observed on a screen.

Answer the questions that follow.
10.2.3 The diagrams below indicate some possible energy transitions made by atoms.

Which ONE of the diagrams could result in the type of spectrum observed in QUESTION 10.2.1? Choose from DIAGRAM A or DIAGRAM B.(2)
Show the memo (1 tick)Memo
1. ✓
  Choice of diagramDiagram B
  2 marks · Explain emission and absorption spectra
6. Question 10.2 · May/June 2022 · Paper 1 · National (DBE) · 2 marks
10.2 Briefly explain how an emission spectrum is formed in terms of energy transitions.(2)
Show the memo (2 ticks)Memo
1. ✓
  Transition to a lower levelAn atom (electron) in higher (excited) energy state/level returns to a lower energy state/level.
  1 mark · Explain emission and absorption spectra
2. ✓
  Energy released as lightEnergy is released as light (photons/frequencies of light are released).
  1 mark · Explain emission and absorption spectra

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