First of all, the photoelectric effect is that the metal will runaway electrons under the irradiation of light. The physical significance of Einstein's equation is that wave is regarded as a particle, and light and some waves without internal texture have wave-particle duality, which lays the foundation for the quantization proposed by Bohr and others.

The second problem is that the cathode is plated with a small work function to make electrons escape more easily, and the anode adopts a work function material to prevent anode electrons from escaping under the action of electric field, which leads to a large experimental error. 、

The third problem is that the intensity of photocurrent is related to light intensity, while the cut-off voltage is independent of light intensity.

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