Einstein S Photoelectric Equation Energy Quantum Of Radiation

Step 1: Principle of photoelectric effect.
The stopping potential depends only on the energy of the photons (i.e., frequency of light), not on intensity or power.

Step 2: Effect of doubling the light power.
Doubling the power doubles the number of photons hitting the metal surface, thus increasing the number of emitted electrons. However, since photon energy remains constant, the stopping potential does not change.

Step 3: Conclusion.
Hence, when the power of the light source is doubled, the stopping potential remains the same.