Concept explainers
(a)
The work function of sodium using the graph.
(a)
Answer to Problem 65AP
The work function of sodium is
Explanation of Solution
Write the equation for the maximum kinetic energy of the ejected photoelectrons.
Here,
Rewrite the above equation for
Write the Einstein’s photoelectric effect equation.
Here,
Put the above equation in equation (I).
Consider the two points
Substitute
Substitute
Conclusion:
Add equations (III) and (IV) and rewrite it for
Substitute
Therefore, the work function of sodium is
(b)
The value of the ratio
(b)
Answer to Problem 65AP
The value of the ratio
Explanation of Solution
Subtract equation (III) from equation (IV).
Conclusion:
Therefore, the value of the ratio
(c)
The cutoff wavelength.
(c)
Answer to Problem 65AP
The cutoff wavelength is
Explanation of Solution
Rewrite Einstein’s photoelectric equation for
At the cutoff wavelength, kinetic energy of the photoelectrons becomes zero.
Substitute
Write the relation between cutoff frequency and cutoff wavelength.
Here,
Put the above equation in equation (V).
Multiply numerator and denominator of right hand side of the above equation by
Conclusion:
The value of
Substitute
Therefore, the cutoff wavelength is
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Chapter 40 Solutions
Physics for Scientists and Engineers with Modern Physics, Technology Update
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