9. Ray optics abd optical instruments — Physics STD 12 Science — Question
CBSE BoardEnglish MediumSTD 12 SciencePhysics9. Ray optics abd optical instruments1 Mark
MCQ
Line spectra are due to
A
Hot solids
✓
Atoms in gaseous state
C
Molecules in gaseous state
D
Liquid at low temperature
✓
Answer
Correct option: B.
Atoms in gaseous state
b Atoms in gaseous state tend to absorb waves of certain wavelength when electromagnetic waves are passed through them. When this light is projected on a photographic film, there are some dark lines caused due to the atoms absorbing waves. This discontinuous spectrum is called line spectrum.
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