Electromagnetic waves
Answers are for parents and teachers.
1
ν = 600 kHz. What is λ in m?
500
2
The Moon is about 3.9·10⁵ km away. How many seconds does a radio wave need? (c = 3·10⁵ km/s)
≈ 1.3 s
3
In a medium with ε = 4 what is the wavelength of a 3 GHz wave in cm? (v = c/2)
5
4
If the frequency doubles, other conditions equal, by what factor does the radiated intensity increase (I ∝ ν⁴)?
16
5
Why does a closed oscillating circuit not emit waves while an open one does?
In a closed circuit the field is confined inside the capacitor and coil; in an open circuit the field lines extend into space.