NTA Abhyas JEE Main2020PhysicsDual Nature of MatterPractice
If n R and n V denote the number of photons emitted by a red bulb and violet bulb of equal power in a given time, then
Options
- An R = n V
- Bn R > n V
- Cn R < n V
- Dn R ≤ n V
Correct answer
B. n R > n V
Step-by-step solution
Energy possessed by a photon is given by E = h f = h c λ If power of each bulb is P then energy given out in time t equal to P t . Let the number of photons be n , then n = P t E = P t ( h c / λ ) = P t λ h c For red light, n R = P t λ R h c For violet light, n V = P t λ V h c ∴ n R n V = λ R λ V As λ R > λ V So, n R > n V