The energy of a photon that has a wavelength of 12.3 nm is

Energy of a photon is calculated using the formula

Ep = (Planck’s constant x speed of light / wavelength)

Ep = (6.634 x 10^-34 J. s x 3 x 108 ms-1) / 12.3 x 10^-9 m

Ep = (6.634 x 10^-34 J. s m s-1 / 12.3 x 10^-9 m

Ep = (19.902 x 10^-26 J. s m s-1) / 12.3 x 10^-9 m

Ep = (19.902 x 10^-26 J. s m s-1) / 12.3 x 10^-9 m

Ep = 1.618 x 10^ - 15 J