Photoelectric Effects and deBroglie Equation: Practice Problem & Solution
A photoelectric cell is illuminated by a point source of light 1 m away. When the source is shifted to 2 m then: (2003)
Solution Explained:
To solve this problem, we apply the core principles of Photoelectric Effects and deBroglie Equation. Understanding the underlying formula is key to arriving at the correct answer below:
Intensity of illumination is inversely proportional to the square of distance ( $I \propto \frac{1}{d^2}$ ). When the distance is shifted from 1 m to 2 m, it doubles, so the intensity becomes one-fourth ( $1/4$ ) of its initial value. Since the number of emitted electrons is directly proportional to intensity, it is reduced to a quarter of the initial number.
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