Photoelectric Kinetic Energy – Rankers Physics

Photoelectric Effects and deBroglie Equation: Practice Problem & Solution

Ultraviolet radiation of \(6.1 \text{eV}\) falls on an aluminium surface of work function \(4.2 \text{eV}\). The kinetic energy of the fastest electron emitted is
\(1.9 \times 10^{-19} \text{J}\)
\(1.6 \times 10^{-19} \text{J}\)
\(3.04 \times 10^{-19} \text{J}\)
\(2.5 \times 10^{-19} \text{J}\)

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:

According to Einstein's photoelectric equation, \(K_{max} = h\nu - \phi = 6.1 \text{eV} - 4.2 \text{eV} = 1.9 \text{eV}\). Converting to Joules: \(1.9 \times 1.6 \times 10^{-19} \text{J} = 3.04 \times 10^{-19} \text{J}\).

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