Physics · Class 12 · Chapter 10
Wave Optics
11 lessons 88 min 2 simulations
Light behaves as a wave. Huygens' construction of wavefronts gives the laws of reflection and refraction, and predicts that light slows down in a denser medium. Two coherent sources add their amplitudes and make the steady bright and dark fringes of Young's double-slit experiment, while a single slit spreads light into a diffraction pattern with a broad central maximum. Polarisation, seen with polaroids and described by Malus' law, shows that light is a transverse wave.
What the exam asks
NEET asks for fringe positions x = nDλ/d and the spacing Dλ/d, the resultant intensity 4I₀cos²(φ/2) with the average 2I₀ for incoherent sources, the single-slit minima at θ = nλ/a, what changes and what stays fixed on refraction, and Malus' law together with the halving at the first polaroid. Marks are lost by dropping the factor ½ for unpolarised light, by letting two independent lamps interfere, and by mixing up the single-slit condition for a minimum with the double-slit condition for a bright fringe.
Lessons
11 lessons · 88 min
1Light as a waveNCERT §10.16 min2Wavefronts and Huygens principleNCERT §10.26 min3Refraction of a plane waveNCERT §10.3.17 min4Rarer medium, reflection and lensesNCERT §10.3.2, §10.3.37 min5Coherent and incoherent additionNCERT §10.46 min6Young's double-slit experimentNCERT §10.511 min 1 sim7Diffraction at a single slitNCERT §10.6, §10.6.17 min8Interference, diffraction and seeing themNCERT §10.6.1, §10.6.27 min9Polarisation of lightNCERT §10.76 min10Malus' law and crossed polaroidsNCERT §10.710 min 1 sim11Chapter reviewMust-know facts, traps and formulas15 min