BRAINCAKEExam Question 6
Question
A student measures the maximum kinetic energy Ek(max) of photoelectrons emitted from a metal for light of several different frequencies f, and plots a graph of Ek(max) against f. The result is a straight line that crosses the frequency axis at 5.0 × 1014 Hz.
(a) Use the photoelectric equation to explain why the graph is a straight line. (2)
(b) State what the gradient of the line represents. (1)
(c) Calculate the work function of the metal. (2)
(d) The experiment is repeated with a metal of larger work function. Describe how the new line compares with the first. (2)
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Key terms in this lesson
- work function
- The minimum energy needed for an electron to escape from the surface of a metal.
- threshold frequency
- The minimum frequency of electromagnetic radiation that will cause photoelectric emission from a given metal surface.
More in Quantum Physics
- Excitation and De-excitation
- Line Spectra
- Exam Question 1
- Exam Question 2
- Exam Question 3
- Exam Question 4
- Exam Question 5
- Exam Question 7
All 21 lessons in Quantum Physics · All Edexcel AS-level Physics topics