In a wave on a string, the amplitude is the maximum displacement of a point on the string from its equilibrium position. What is the amplitude of an electromagnetic wave?
Estimate the wavelength of your favorite radio station.
At a given distance, say, 3 m, the light from a 200 W lightbulb is brighter than the light from a 60 W lightbulb. Does this means that light coming from the 200 W bulb has a larger electric field? a larger magnetic field? A higher frequency? A longer wavelength?
Light from the Sun reaches the Earth's atmosphere at a rate of about 1350 W/m2. Assuming that this light is entirely absorbed, estimate the force exerted on the Earth due to radiation pressure. Is this significant compared to the force on Earth due to the Sun's gravitational attraction?
