Answer:
f =1 10⁸ Hz
Explanation:
The speed of an electromagnetic wave is given by
c = Lam f
In our case, the wavelength is 3.0 m, so we can clear the frequency
f = c / Lam
f = 3 108/3.
f =1 10⁸ Hz
The electrons stop flowing
density = mass/volume = 100kg/10ml = 10kg/ml
voluime = mass/density = 50g/2 g/ml = 25 ml
mass = density x volume = 2x55 = 110 kg