KCET 2025 Physics Paper

When light passes into a non-reflecting, non-absorbing medium, no energy is lost at the boundary. In particular:Energy flux is given by the (time-averaged) Poynting vector$\vec{S}=\vec{E}\times\vec{H}$For no reflection and no absorption, the tangential components of both fields are continuous across the interface: $E_1=E_2, \;\; H_1=H_2 .$Hence the incident and transmitted fluxes are equal:$S_1=E_1 H_1=E_2 H_2=S_2$Since all the energy that arrives is carried forward, the total energy carried by the wave remains the same.Answer: Option A (remains same).