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The work function of a certain metal is ...

The work function of a certain metal is `3.31xx10^(-19) j`then, the maximum kinetic energy of photoelectrons emitted by incident radiation of wavelength `5000`Å IS(GIVEN,h=`6.62XX10^(-34)J_(-s),c=3xx10^(8)ms^(-1),e=1.6xx10^(-19)C)`

A

2.48 eV

B

0.41 eV

C

2.07 eV

D

0.82 eV

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The correct Answer is:
To find the maximum kinetic energy of photoelectrons emitted by incident radiation of wavelength \(5000 \, \text{Å}\) (or \(5000 \times 10^{-10} \, \text{m}\)), we can follow these steps: ### Step-by-Step Solution: 1. **Convert Wavelength to Meters:** \[ \text{Wavelength} (\lambda) = 5000 \, \text{Å} = 5000 \times 10^{-10} \, \text{m} = 5.0 \times 10^{-7} \, \text{m} \] 2. **Calculate the Energy of the Incident Photon:** The energy of a photon can be calculated using the formula: \[ E = \frac{hc}{\lambda} \] where: - \(h = 6.62 \times 10^{-34} \, \text{J s}\) (Planck's constant) - \(c = 3 \times 10^{8} \, \text{m/s}\) (speed of light) Substituting the values: \[ E = \frac{(6.62 \times 10^{-34} \, \text{J s})(3 \times 10^{8} \, \text{m/s})}{5.0 \times 10^{-7} \, \text{m}} \] \[ E = \frac{1.986 \times 10^{-25} \, \text{J m}}{5.0 \times 10^{-7} \, \text{m}} = 3.972 \times 10^{-19} \, \text{J} \] 3. **Convert the Work Function to Electron Volts:** The work function \(W\) is given as \(3.31 \times 10^{-19} \, \text{J}\). To convert this to electron volts: \[ W = \frac{3.31 \times 10^{-19} \, \text{J}}{1.6 \times 10^{-19} \, \text{J/eV}} \approx 2.06875 \, \text{eV} \] 4. **Calculate the Maximum Kinetic Energy of the Photoelectrons:** The maximum kinetic energy \(K.E.\) of the emitted photoelectrons can be calculated using the formula: \[ K.E. = E - W \] Substituting the values: \[ K.E. = (3.972 \times 10^{-19} \, \text{J}) - (3.31 \times 10^{-19} \, \text{J}) = 6.62 \times 10^{-20} \, \text{J} \] 5. **Convert Kinetic Energy to Electron Volts:** \[ K.E. = \frac{6.62 \times 10^{-20} \, \text{J}}{1.6 \times 10^{-19} \, \text{J/eV}} \approx 0.41375 \, \text{eV} \] ### Final Answer: The maximum kinetic energy of the photoelectrons emitted is approximately \(0.41 \, \text{eV}\). ---
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