According to the cosine law, to minimize reflection and maximize absorption, the energy source must be at a ___ angle to the surface.

According to the cosine law, to minimize reflection and maximize absorption, the energy source must be at a ___ angle to the surface.

According to the cosine law, to minimize reflection and maximize absorption, the energy source must be at a ___ angle to the surface.


45 degree
90 degree
180 degree
0 degree


Answer: 90 degrees