1. Starting from Maxwell's equations, derive a wave equation for the magnetic field and show

that a harmonic plane wave prorogating along x direction is a solution. Prove it is a transverse

wave.

2. Consider sunlight at the top of Earth's atmosphere. The sun-earth distance is 500 light-second.

The sun's total power radiation is 3.9×1026 W.

(1) What is the sunlight intensity?

(2) What is the electric field amplitude?

(3) How does its magnetic field amplitude compare to the Earth's magnetic field?