Planck's relation is the formula which links the energy in Joules(E) of a photon with its frequency in Hertz (v) through Planck's Constant(`h=6.626*10^-34 J*S` ).

`E=hv`

As a photon is a quantum of electromagnetic energy, we can calculate the energy of a single quantum by plugging in the value above...

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Planck's relation is the formula which links the energy in Joules(E) of a photon with its frequency in Hertz (v) through Planck's Constant(`h=6.626*10^-34 J*S` ).

`E=hv`

As a photon is a quantum of electromagnetic energy, we can calculate the energy of a single quantum by plugging in the value above and looking up Planck's Constant.

`E=hv~~(6.626*10^-34)*(2.88*10^10)=1.9083*10^-23`

Now we know the energy of a single quantum, it's simple to calculate the number of quanta required to have `7.06*10^4` Joules.

If we call `E_t` the total energy required and `E_p` the energy of a single photon, then the number of quanta required, n, is calculated using the formulae

`E_t=nE_p`

`n=E_p/E_t=hv/E_t~~((6.626*10^34)*(2.88*10^10))/(7.06*10^4)=2.703*10^40`