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Current Question (ID: 7494)

Question:

The ejection of the photoelectron from the silver metal can be stopped by applying a voltage of 0.35 eV when the radiation having a wavelength of 256.7 nm is used. The work function for silver metal is:

Options:

1. 3.40 eV
2. 5.18 eV
3. 4.48 eV
4. -4.40 eV

Solution:

### **Hint:** Photoelectric effect equation $E = W_0 + K.E.$ **Step 1:** Calculate the energy of the incident photon: \[E = \frac{hc}{\lambda} = \frac{(6.626 \times 10^{-34} \text{Js})(3 \times 10^8 \text{ms}^{-1})}{256.7 \times 10^{-9} \text{m}} = 7.744 \times 10^{-19} \text{J}\] Convert to eV: \[E = 7.744 \times 10^{-19} \text{J} \times 6.24 \times 10^{18} \text{eV/J} = 4.83 \text{eV}\] **Step 2:** The stopping voltage (0.35 eV) equals the kinetic energy of the photoelectron. Calculate work function: \[W_0 = E - K.E. = 4.83 \text{eV} - 0.35 \text{eV} = 4.48 \text{eV}\] Thus, the correct answer is 4.48 eV.

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Upload a JSON file containing LaTeX/MathJax formatted question, options, and solution.

Expected JSON Format:

{
  "question": "The mass of carbon present in 0.5 mole of $\\mathrm{K}_4[\\mathrm{Fe(CN)}_6]$ is:",
  "options": [
    {
      "id": 1,
      "text": "1.8 g"
    },
    {
      "id": 2,
      "text": "18 g"
    },
    {
      "id": 3,
      "text": "3.6 g"
    },
    {
      "id": 4,
      "text": "36 g"
    }
  ],
  "solution": "\\begin{align}\n&\\text{Hint: Mole concept}\\\\\n&1 \\text{ mole of } \\mathrm{K}_4[\\mathrm{Fe(CN)}_6] = 6 \\text{ moles of carbon atom}\\\\\n&0.5 \\text{ mole of } \\mathrm{K}_4[\\mathrm{Fe(CN)}_6] = 6 \\times 0.5 \\text{ mol} = 3 \\text{ mol}\\\\\n&1 \\text{ mol of carbon} = 12 \\text{ g}\\\\\n&3 \\text{ mol carbon} = 12 \\times 3 = 36 \\text{ g}\\\\\n&\\text{Hence, 36 g mass of carbon present in 0.5 mole of } \\mathrm{K}_4[\\mathrm{Fe(CN)}_6].\n\\end{align}",
  "correct_answer": 4
}