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Atomic spectra
5 Class 12 Physics questions with answers and explanations.
Printable worksheet with answer key
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In the Bohr model, electrons orbit in:
- 1 Any orbit
- 2 Elliptical only
- 3 Straight lines
- 4 Fixed energy levels
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Correct answer: Fixed energy levels
Only certain orbits with fixed energies are allowed.
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The Lyman series corresponds to transitions ending at:
- 1 n = 3
- 2 n = 1
- 3 n = 4
- 4 n = 2
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Correct answer: n = 1
Lyman lines are in the ultraviolet and end at n = 1.
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X rays are produced when fast electrons:
- 1 Are slowed in water only
- 2 Hit a metal target
- 3 Are reflected by glass
- 4 Pass through air
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Correct answer: Hit a metal target
Sudden deceleration of electrons in a target produces X rays.
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LASER stands for light amplification by:
- 1 Stimulated emission of radiation
- 2 Selective emission of rays
- 3 Spontaneous emission of rays
- 4 Stimulated electrons
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Correct answer: Stimulated emission of radiation
This is the meaning of the word.
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The wavelength emitted when an atom jumps between levels depends on:
- 1 The energy difference of the levels
- 2 The temperature only
- 3 Its mass
- 4 The atom's colour
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Correct answer: The energy difference of the levels
E = h c / wavelength equals the energy difference.