COMEDK2024Morning ShiftPhysicsDual Nature of MatterActual
The threshold frequency for a metal surface is ' n₀ '. A photo electric current ' I ' is produced when it is exposed to a light of frequency ( 11 6 ) n _ o and intensity I _ n . If both the frequency and intensity are halved, the new photoelectric current ' I ^1 ' will become:
Options
- AI ^1=2 I
- BI^1=0
- CI ^1= 1 2 I
- DI ^1= 1 4 I
Correct answer
B. I^1=0
Step-by-step solution
The photoelectric effect occurs only when the incident frequency is greater than or equal to the threshold frequency ₀ . Initially, the incident frequency is ₁ = 11 6 ₀ . Since ₁ > ₀ , photoelectric emission occurs, and the current is I . When the frequency is halved, the new frequency becomes ₂ = 1 2 11 6 ₀ = 11 12 ₀ . Comparing ₂ with the threshold frequency ₀ , we observe that ₂ = 11 12 ₀ Since the new incident frequency is less than the threshold frequency, no photoelectric emission can take place, regardless o