Question

In photoelectric effect, the photo current

• A. does not depend on the frequency of photon but depends on intensity of incident light.
• B. decreases with Increase in frequency of incident photon.
• C. increases with increase in frequency of incident photon.
• D. depends with on intensity of incident radiation and its frequency.

Hint:

Remember this direct pairing for the photoelectric effect: Intensity controls the quantity (photoelectric current), while Frequency controls the quality or energy (stopping potential / kinetic energy).

Answer 1

The Correct Option is A

Step 1: Understand what photo current means.
In the photoelectric effect, light ejects electrons from a metal. The photo current is just the flow rate of these ejected electrons, so it depends on how many electrons leave per second.
Step 2: Recall the two light properties.
Light has frequency (how energetic each photon is) and intensity (how many photons arrive per second, for a fixed frequency).
Step 3: One photon, one electron.
Above the threshold frequency, each absorbed photon frees one electron. So the number of electrons freed per second tracks the number of photons arriving per second.
Step 4: Role of intensity.
Higher intensity means more photons per second, hence more electrons freed per second, hence a larger photo current. So photo current rises with intensity.
Step 5: Role of frequency.
Raising the frequency (still above threshold) gives each electron more kinetic energy but does not change how many photons arrive. So the count of electrons per second, and thus the photo current, does not depend on frequency.
Step 6: Conclude.
Photo current depends on intensity but not on frequency, which is option (1).
\[ \boxed{\text{Photo current depends on intensity, not on frequency}} \]