NEETChemistryStructure of Atom
Two light sources, A and B, emit the exact same number of photons per second. Source A has a power rating of 60 W and converts 10 % of its energy into light. Source B has a power rating of 100 W and converts 3 % of its energy into light. What is the ratio of the wavelength of light emitted by source A to that of source B ( _A : _B )?
Options
- A2:1
- B5:3
- C1:2
- D3:5
Correct answer
C. 1:2
Step-by-step solution
Useful power of source A, P_A' = 60 10 100 = 6 W Useful power of source B, P_B' = 100 3 100 = 3 W The energy of one photon is given by E = hc . The number of photons emitted per second is n = P' E = P' hc . Given that n_A = n_B , we can write: P_A' _A hc = P_B' _B hc P_A' _A = P_B' _B 6 _A = 3 _B _A _B = 3 6 = 1 2 The ratio of their wavelengths is 1:2 . Answer: 1:2