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The kinetic energy of the most energetic electron is given by E - W₀, where E = 6.2 eV and W₀ = 4.2 eV. Calculate the result in joules.

1. 3.2×10^-19 J
2. 2.0×10^-19 J
3. 4.2×10^-19 J
4. None of the above

Correct answer: 3.2×10^-19 J

Solution

The kinetic energy of the fastest electron is calculated as K.E. = E - W₀, where E is the energy of the incident photon and W₀ is the work function. Substituting the given values, K.E. = 6.2 eV - 4.2 eV = 2.0 eV, which converts to 3.2×10^-19 J. Thus, option A is correct.

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