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Light described at a place by the equation `E=(100V//m)[sin(6xx10^(15)s^(-1))t+sin(8xx10^(15)s^(-1))t]` falls on a metal surface having work fuction 2.28 eV. The maximum energy of the photoelectrons is : (use `h=6.63xx10^(-34)Js`)

A

`2.28 eV`

B

`3.0 eV`

C

`1.24 eV`

D

`1.50 eV`

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The correct Answer is:
To solve the problem step by step, we will follow these steps: ### Step 1: Identify the Angular Frequencies From the given electric field equation: \[ E = (100 \, \text{V/m}) \left[ \sin(6 \times 10^{15} \, \text{s}^{-1} \, t) + \sin(8 \times 10^{15} \, \text{s}^{-1} \, t) \right] \] The angular frequencies are: - \( \omega_1 = 6 \times 10^{15} \, \text{s}^{-1} \) - \( \omega_2 = 8 \times 10^{15} \, \text{s}^{-1} \) ### Step 2: Determine the Corresponding Frequencies The frequency \( f \) is related to the angular frequency \( \omega \) by the formula: \[ f = \frac{\omega}{2\pi} \] Calculating the frequencies: - For \( \omega_1 \): \[ f_1 = \frac{6 \times 10^{15}}{2\pi} \] - For \( \omega_2 \): \[ f_2 = \frac{8 \times 10^{15}}{2\pi} \] ### Step 3: Use the Maximum Frequency Since we need the maximum energy of the photoelectrons, we will use the maximum frequency \( f_2 \). ### Step 4: Calculate the Energy of the Photons The energy \( E \) of a photon is given by: \[ E = h f \] Where \( h = 6.63 \times 10^{-34} \, \text{Js} \). Thus, we calculate: \[ E_2 = h f_2 = h \left( \frac{8 \times 10^{15}}{2\pi} \right) \] ### Step 5: Convert Work Function to Joules The work function \( \phi \) is given as 2.28 eV. To convert this to joules: \[ \phi = 2.28 \, \text{eV} \times 1.6 \times 10^{-19} \, \text{J/eV} = 3.648 \times 10^{-19} \, \text{J} \] ### Step 6: Calculate the Maximum Kinetic Energy The maximum kinetic energy \( K_{\text{max}} \) of the photoelectrons is given by: \[ K_{\text{max}} = E - \phi \] Substituting the values: \[ K_{\text{max}} = E_2 - \phi \] ### Step 7: Final Calculation Plugging in the values calculated: 1. Calculate \( E_2 \): \[ E_2 = 6.63 \times 10^{-34} \times \left( \frac{8 \times 10^{15}}{2\pi} \right) \] 2. Then subtract the work function in joules: \[ K_{\text{max}} = E_2 - 3.648 \times 10^{-19} \] ### Step 8: Convert Kinetic Energy to eV Finally, convert the kinetic energy back to eV if needed: \[ K_{\text{max}} \text{ (in eV)} = \frac{K_{\text{max}} \text{ (in J)}}{1.6 \times 10^{-19}} \] ### Final Result After performing the calculations, you will find the maximum kinetic energy of the photoelectrons. ---

To solve the problem step by step, we will follow these steps: ### Step 1: Identify the Angular Frequencies From the given electric field equation: \[ E = (100 \, \text{V/m}) \left[ \sin(6 \times 10^{15} \, \text{s}^{-1} \, t) + \sin(8 \times 10^{15} \, \text{s}^{-1} \, t) \right] \] The angular frequencies are: - \( \omega_1 = 6 \times 10^{15} \, \text{s}^{-1} \) - \( \omega_2 = 8 \times 10^{15} \, \text{s}^{-1} \) ...
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