Question

How much energy in kJ is associated with a radio wave of wavelength 1.2 X 10^2 m?

Can I get a step by step explanation. I haven't learned anything about energy or wavelength before so this is my first time coming across a problem like this

Answer 1

It's very simple.

Energy =
`(hc)/(\lambda)`

where, h= Planck's constant = 6.6 x
`10^(-34)`
`m^2 kg/s`

c= speed of light = 3 x
`10^(8)` m/s

`\lambda` = wavelength


So, energy =
`(6.6 * 10^(-34) * 3 * 10^(8))/(120)`

= 1.65 x
`10^(-27)` J
=1.65 x
`10^(-30)` KJ