Answer:
Frequency, 
Explanation:
We have,
Speed of radio waves is 
Wavelength of radio waves is 
It is required to find the frequency of the radio waves. The speed of a wave is given by :

So, the frequency of the radio wave is
.
Answer:
we know that current = charge/time
Explanation:
therefore,
A = 8000/120
A => 66.666.... amperes
You can keep it for as long as you want; you're the boss of your fridge.
But anyway, an open beer bottle can stay good in the fridge for up to 96 hours, probably more.