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Photoelectric threshold of silver is lam...

Photoelectric threshold of silver is `lamda=3800A`. Ultraviolet light of `lamda=2600A` is incident of a silver surface.(Mass of the electron `9.11xx10^(-31)kg`)`
1. Calculate the value of work function is eV.

A

1.77

B

3.27

C

5.69

D

2.32

Text Solution

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The correct Answer is:
To calculate the work function of silver in electron volts, we will follow these steps: ### Step 1: Convert the wavelength of the threshold (λ₀) from Angstroms to meters. Given: - λ₀ = 3800 Å = 3800 × 10⁻¹⁰ m ### Step 2: Calculate the frequency (f₀) corresponding to the threshold wavelength (λ₀). Using the formula: \[ f = \frac{c}{\lambda} \] where: - c = speed of light = \( 3 \times 10^8 \) m/s Substituting the values: \[ f₀ = \frac{3 \times 10^8 \text{ m/s}}{3800 \times 10^{-10} \text{ m}} \] ### Step 3: Calculate the work function (W) using the frequency (f₀). The work function can be calculated using the formula: \[ W = h f₀ \] where: - h = Planck's constant = \( 6.63 \times 10^{-34} \) J·s Substituting the frequency calculated in Step 2 into the equation: \[ W = 6.63 \times 10^{-34} \text{ J·s} \times f₀ \] ### Step 4: Convert the work function from joules to electron volts. To convert joules to electron volts, use the conversion factor: 1 eV = \( 1.6 \times 10^{-19} \) J Thus, \[ W \text{ (in eV)} = \frac{W \text{ (in J)}}{1.6 \times 10^{-19}} \] ### Step 5: Calculate the value of the work function in eV. Now, we will perform the calculations step by step. 1. **Calculate frequency (f₀)**: \[ f₀ = \frac{3 \times 10^8}{3800 \times 10^{-10}} = \frac{3 \times 10^8}{3.8 \times 10^{-7}} \approx 7.89 \times 10^{14} \text{ Hz} \] 2. **Calculate work function (W) in joules**: \[ W = 6.63 \times 10^{-34} \times 7.89 \times 10^{14} \approx 5.22 \times 10^{-19} \text{ J} \] 3. **Convert work function to eV**: \[ W \text{ (in eV)} = \frac{5.22 \times 10^{-19}}{1.6 \times 10^{-19}} \approx 3.26 \text{ eV} \] Thus, the work function of silver is approximately **3.26 eV**.

To calculate the work function of silver in electron volts, we will follow these steps: ### Step 1: Convert the wavelength of the threshold (λ₀) from Angstroms to meters. Given: - λ₀ = 3800 Å = 3800 × 10⁻¹⁰ m ### Step 2: Calculate the frequency (f₀) corresponding to the threshold wavelength (λ₀). Using the formula: ...
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