Arrange the following electromagnetic radiations in ascending order of their energies.
A. Blue light
B. Yellow light
C. X-ray
D. Radio-wave
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → D, B, A, C
The energy of a photon is \( E = h\nu = hc/\lambda \), so the energy rises with frequency: the shorter the wavelength, the higher the energy.
\( \text{(D) Radio-wave: } \lambda \gt 0.1\,\mathrm{m} \)
\( \text{(B) Yellow light: } \lambda \approx 580\,\mathrm{nm} \)
\( \text{(A) Blue light: } \lambda \approx 450\,\mathrm{nm} \)
\( \text{(C) X-ray: } \lambda \sim 0.1\,\mathrm{nm} \)
The wavelength falls from (D) to (C), so the ascending order of energy is D, B, A, C.