Planck's equation states that
E = hf
where
E = the energy,
h = Planck's constant
f = the frequency
Because
c = fλ
where
c = velocity of light,
λ = wavelength
therefore
E = h(c/λ)
Photon #1:
The wavelength is λ₁ = 60 nm.
The energy is
E₁ = (hc)/λ₁
Photon #2:
The energy is twice that of photon #1, therefore its energy is
E₂ = 2E₁ = (hc)/λ₂.
Therefore
Answer: 30 nm
E = hf
where
E = the energy,
h = Planck's constant
f = the frequency
Because
c = fλ
where
c = velocity of light,
λ = wavelength
therefore
E = h(c/λ)
Photon #1:
The wavelength is λ₁ = 60 nm.
The energy is
E₁ = (hc)/λ₁
Photon #2:
The energy is twice that of photon #1, therefore its energy is
E₂ = 2E₁ = (hc)/λ₂.
Therefore
Answer: 30 nm