Who discovered photo electric effect ?

Options

A. Hertz
B. Lenard
C. Hallwach
D. Einstein

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks who discovered the photoelectric effect.

2. **Consider the Options**: The options provided are Hodge, Lenard, Elavich, and Einstein.

3. **Recall Historical Context**: The photoelectric effect is a phenomenon where electrons are emitted from a material when it is exposed to light. This effect was crucial in the development of quantum theory.

4. **Identify the Correct Answer**: Albert Einstein is credited with the discovery of the photoelectric effect in 1905. His work explained how light behaves as both a wave and a particle, introducing the concept of photons.

5. **Recognition of Achievement**: In recognition of his work on the photoelectric effect, Albert Einstein was awarded the Nobel Prize in Physics in 1921.

6. **Conclusion**: Therefore, the correct answer to the question "Who discovered the photoelectric effect?" is Albert Einstein.

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