Attempt 4

Given:
- The work function: [tex]4.60 \times 10^{-19} \, J[/tex]
- The maximum wavelength: [tex]\lambda_{\max} = 4.32 \times 10^{-7} \, m[/tex]
- The maximum speed of the emitted photoelectrons: [tex]2.33 \times 10^6 \, m/s[/tex]

Question:
What wavelength of electromagnetic radiation struck the surface and caused the ejection of the photoelectrons?

[tex]\lambda = \square \times 10^y \, \text{m}[/tex]



Answer :

Sure, let's go through the problem step-by-step to find the wavelength of the electromagnetic radiation that struck the surface and caused the ejection of photoelectrons.

### Given Data:
1. Work Function, [tex]\( \phi \)[/tex]:
[tex]\[ \phi = 4.60 \times 10^{-19} \, \text{J} \][/tex]

2. Maximum Speed of Emitted Photoelectrons, [tex]\( v_{\text{max}} \)[/tex]:
[tex]\[ v_{\text{max}} = 2.33 \times 10^6 \, \text{m/s} \][/tex]

3. Planck's Constant, [tex]\( h \)[/tex]:
[tex]\[ h = 6.62607015 \times 10^{-34} \, \text{J} \cdot \text{s} \][/tex]

4. Speed of Light, [tex]\( c \)[/tex]:
[tex]\[ c = 3.0 \times 10^8 \, \text{m/s} \][/tex]

5. Mass of an Electron, [tex]\( m_e \)[/tex]:
[tex]\[ m_e = 9.10938356 \times 10^{-31} \, \text{kg} \][/tex]

### Step-by-Step Solution:

Step 1: Calculate Kinetic Energy of Photoelectrons

The kinetic energy [tex]\( KE \)[/tex] of the photoelectrons can be calculated using their maximum speed. The formula for kinetic energy is:
[tex]\[ KE = \frac{1}{2} m_e v_{\text{max}}^2 \][/tex]

Substituting the given values:
[tex]\[ KE = \frac{1}{2} \times 9.10938356 \times 10^{-31} \, \text{kg} \times (2.33 \times 10^6 \, \text{m/s})^2 \][/tex]

[tex]\[ KE = 2.4726966204442 \times 10^{-18} \, \text{J} \][/tex]

Step 2: Calculate Total Energy of Incident Photons

The total energy [tex]\( E \)[/tex] of the incident photons is the sum of the work function [tex]\( \phi \)[/tex] and the kinetic energy [tex]\( KE \)[/tex]:
[tex]\[ E = \phi + KE \][/tex]

Substituting the given and calculated values:
[tex]\[ E = 4.60 \times 10^{-19} \, \text{J} + 2.4726966204442 \times 10^{-18} \, \text{J} \][/tex]

[tex]\[ E = 2.9326966204441997 \times 10^{-18} \, \text{J} \][/tex]

Step 3: Calculate Wavelength of the Incident Radiation

The wavelength [tex]\( \lambda \)[/tex] of the incident radiation can be calculated using the energy of the photons. The relationship between the energy [tex]\( E \)[/tex] of a photon and its wavelength [tex]\( \lambda \)[/tex] is given by the equation:
[tex]\[ \lambda = \frac{h \cdot c}{E} \][/tex]

Substituting the given and calculated values:
[tex]\[ \lambda = \frac{6.62607015 \times 10^{-34} \, \text{J} \cdot \text{s} \times 3.0 \times 10^8 \, \text{m/s}}{2.9326966204441997 \times 10^{-18} \, \text{J}} \][/tex]

[tex]\[ \lambda = 6.778133923374983 \times 10^{-8} \, \text{m} \][/tex]

### Conclusion

The wavelength of the electromagnetic radiation that struck the surface and caused the ejection of the photoelectrons is:
[tex]\[ \lambda = 6.778133923374983 \times 10^{-8} \, \text{m} \][/tex]