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#denser medium

2 public questions tagged with this topic.

Why does the intensity of light not depend on its speed when it enters a denser medium?

**Polaroid rotation** intensity varies sinusoidally with angle due to Malus law I = I₀ cos²θ, when polaroid rotated 90° from initial, intensity goes from max to zero, for unpolarized light rotating polaroid does not change intensity after first polaroid because average, but second polaroid intensity depends on relative angle, explains why intensity transmitted through two polaroids drops to zero when perpendicular. Intensity depends on the amplitude squared, not speed, which only affects wavelength and not the energy carried per unit area. Using Δ = d sinθ, y = n λ D/d, a sinθ = n λ, I = I₀ co

Ref: NCERT > Physics Book > Wave Optics > Polarization and Malus Law

What happens to the wavelength of light when it enters a denser medium?

**Frequency of light** remains unchanged when refracts from air into water because frequency determined by source, energy E= h f conserved, speed decreases v= c/n, wavelength decreases λ'=v/f= λ/n, energy of wave proportional to amplitude² not speed, intensity I =½ c ε₀ E₀², energy not depend on speed directly, when speed decreases amplitude may change but energy conserved, interference redistributes energy, total energy same, bright regions gain from dark. In a denser medium, the speed decreases, and since frequency remains constant, wavelength decreases ( λ = (v/nu) ). Using Δ = d sinθ, y =

Ref: NCERT > Physics Book > Wave Optics > Wave Properties, Frequency and Energy Conservation