Wave Optics — Important Questions

Same frequency, Constant phase difference, Derived from the same source

Coherent sources must have the same frequency and maintain a constant phase difference over time. They are typically derived from the same original source to ensure phase coherence. Same amplitude and intensity are not necessary for coherence.

sin θ = λ/a

For single slit diffraction, the first minimum occurs when sin θ = λ/a, where λ is the wavelength and 'a' is the width of the slit. This is derived from the condition for destructive interference in single slit diffraction.

Light waves are transverse in nature, Polaroids can reduce light intensity, Polarization proves the wave nature of light

Light waves are transverse electromagnetic waves, which allows for polarization. Polaroids can control and reduce light intensity. Natural sunlight is unpolarized. Sound waves are longitudinal and cannot be polarized like light waves.

I = I₀ cos² θ

Malus' law states that when polarized light of intensity I₀ passes through a polaroid whose pass-axis makes an angle θ with the direction of polarization, the transmitted intensity is I = I₀ cos² θ.