Originally posted by Bedlam
The emission of a 28kHz radio signal 13 feet across - that ought to warn you right there.
Who knows why? Class? Raise your hand if you know the answer.
I typed 28 in the input box here and then selected kHz:
So that's a hint, but some people might not know what 3.5e+4 feet means in the output box.
This has a more readable output but feet isn't an option, meters would be the closest choice:
Those might be off by about 1% in the atmosphere since it isn't a vacuum, but it's close enough to make the point.