APPhysics2:ElectromagneticWavesClasswork8-1
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Chapter 22
1. Calculate the wavelength of a 20 Hz wave, a 97.1MHz wave, and a red laser light (4.75x1014Hz).
2. I speak into my cellphone and it sends a signal to an antenna 5.0 km away. It then relays the signal to
a satellite 450 km above the ground. It then gets sent back to an antenna (450 km again) and sent to
another person in the room with me 5.0 km away from that antenna. How much time passes before the
person across the room gets my message? (Hint: Use ∆
where
∆
v is speed – the speed of light- Δx
is distance travelled, and Δt is time)
3. Maxwell came up with the idea to divide the electric field by the magnetic field to calculate the speed
of an electromagnetic wave. If an electric field of a radio wave has a magnitude of 1.56x103V/m, what is
the magnitude of the magnetic field?
Chapter 23
4. A light beam is incident on a mirror at an angle of 25o to the normal. What is the reflected angle?
5. I want to see myself (from my head to my feet) in a mirror. How tall does the flat mirror need to be?
Draw a picture to prove this.
6. What would the moon look like (from Earth) if it had large rocks instead of small, regolith? What if
the moon was polished and perfectly smooth?