Coherent sources are those that emit waves of
A{'text': 'Same frequency AND a constant phase difference in time', 'label': 'A'}
B{'text': 'Same intensity only, without any relationship of frequencies', 'label': 'B'}
C{'text': 'Same wavelength only, regardless of the phase behaviour', 'label': 'C'}
D{'text': 'Different frequencies but a similar overall intensity level', 'label': 'D'}
Answer & Solution
Correct answer: A. {'text': 'Same frequency AND a constant phase difference in time', 'label': 'A'}
1. Sustained interference requires coherent sources.
2. Coherent sources emit waves with the same frequency (wavelength).
3. They must also maintain a constant phase difference over time.
4. Two independent light bulbs are not coherent; a laser output is.
_Source: NCERT Class 12 Physics, Ch 10 "Wave Optics", §10.4_
Related questions
Newton originally supported the corpuscular theory of light. The wave theory was strongly In a Young's double-slit experiment, a thin transparent sheet of thickness t and refractivIf polarised light of intensity I passes through a polariser whose axis makes angle θ withAn unpolarised light of intensity I₀ passes through a polariser. The transmitted intensityWhich of the following phenomena is characteristic ONLY of transverse waves and NOT of lonThe polarising angle (Brewster angle) for glass of refractive index 1.5 isThe width of the central maximum in single-slit diffraction on a screen at distance D isFor diffraction at a single slit of width a, the angular position of the first minimum is