Class 12 Physics Photons Notes and Important Questions
Learn
Loading notes…
Notes for Class 12 Photons (Physics) are shown above.
Practice
Important Questions
Ultraviolet radiation of frequency is incident on the surface of an aluminium plate whose work function is
Show that the maximum speed of the electrons emitted from the surface of the aluminium is $8.6 \times 10^{5}\,\text{m s}^{-1}$
State and explain what change, if any, occurs to the maximum speed of the emitted electrons when the intensity of the ultraviolet radiation is increased.
The graph below shows the maximum kinetic energy of the emitted photoelectrons as the frequency of the incident radiation on a sodium plate is varied.
From the graph determine the maximum frequency of incident radiation that can cause a photoelectric effect.
Calculate the work function for sodium.
Use the graph to calculate the value of the Planck constant in $\text{J s}$.
Exam
Past Question Analysis
Historical exam-pattern data from past NEB question papers — not a prediction of future questions.
7
Question Items
0
Total Marks
4
Papers Appeared In
| Year | Question Items | Marks |
|---|---|---|
| 2083 | 3 | — |
| 2082 | 2 | — |
| 2081 | 1 | — |
| 2080 | 1 | — |
The quantum nature of light is introduced through the concept of photons and the photoelectric effect. Students study Einstein's photoelectric equation, work function, threshold frequency, stopping potential and Planck's constant.
This page covers Photons, chapter 21 of 25 in the Class 12 Physics syllabus set by the National Examination Board (NEB). 2 important questions for this chapter are available, each with a full solution.
For numerical and derivation-based chapters like this one, working through past NEB questions is usually more useful than re-reading notes alone — try solving each important question above before checking the solution, then compare your working step by step.