light and energy conservation

[Ari1584]

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So im just wondering bc it seems like these sort of questions are always on practice exams...is energy and momentum conserved during:

1.) Reflection of light

2.) Refraction of light

And can someone explain their reasoning to their answer please too?
Thanks! 😳

 

[BloodySurgeon]

Energy is conserved since the frequency of the light will not change: E=hf. Therefore the energy reflected plus the energy refracted must add up to equal the energy carried by the incident light

Momentum is not conserved since it is a vector quantity and therefore will change direction in both reflectance and refractance.