Wavelengths of different radiations are given below :

According to Planck’s quantum theory, energy is related to the frequency of radiation by :

E = h × Frequency

So, E is proportional to 1/ λ

Hence, the relation b/w energy and wavelength are inversely proportional, therefore lesser the wavelength higher will be the energy of the radiation.

For the given wavelengths

λ(A) = 300 nm = 300 x 10-9 m = 3 x 10 -7 m

λ(B) = 300 μm = 3 00 x 10-6 = 3 x 10-4

λ(c) = 3 nm = 3 x 10 – 9

λ (D) 30 A° = 3 X 10 – 9

the increasing order of the given wavelengths : λ(c) = λ (D) <λ(A)< λ(B)

hence the increasing order of energy will be the opposite: λ(B)< λ(A:<λ(c) = λ (D)