What is the energy, in joules, of a wave with a frequency of #6.78 * 10^7# Hz? What type of wave is this?

1 Answer
Gió
Dec 11, 2015

I think it is a FM radio signal with photon energy of around #4.49xx10^-26J#.

Explanation:

Let us check (as an exercise) the wavelength #lambda# of this wave using:
#c=lambda*nu#
where:
#c=3xx10^8m/s# is the sped of light;
#nu=6.78xx10^7Hz# is the frequency.
so you get:
#lambda=(3xx10^8)/(6.78xx10^7)=4.42m# quite a big wavelength!
considering:

![www2.lbl.gov)

I would say that it falls into the FM radio range.

The energy can be calculated from Einstein's Relationship:
#color(red)(E=hnu)#
Where:
#h=6.63xx10^-34Js# is Planck's constant.
So:
#E=6.63xx10^-35*6.78xx10^7=4.49xx10^-26J#

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