The solution of problem 3.15 cr 3 from the problem book

Task 3.15
A plane electromagnetic wave propagates in the medium (? = 3,? = 1). Amplitude of tension
The magnetic field of the wave is 0.5 A / m. On its way it is perpendicular to a direction of distribution
There is an absorbing surface, which has the form of a circle with a radius of 0.1 m. What is the energy
Absorption by this surface in a time t = 30 s? The period of the wave is T << t.