CBSE Class 12 Physics Question Bank 2026: Dual Nature & Photoelectric Effect
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Mastering the CBSE Class 12 Physics Question Bank 2026
The CBSE Class 12 Physics Question Bank 2026 is your ultimate resource for mastering Chapter 11: Dual Nature of Radiation and Matter. In the current 2026 examination cycle, this unit holds significant weightage, often contributing nearly 4 to 6 marks in the theory paper. Understanding the dual behavior of light and matter is not just essential for boards but is a foundational pillar for medical entrance exams like NEET and engineering papers like JEE.
As students prepare for the 2026 boards, the shift toward competency-based questions means you must understand the "why" behind every phenomenon. Whether it is the particle nature of light proven by the photoelectric effect or the wave nature of matter proposed by de-Broglie, this chapter bridges the gap between classical and modern physics.
Syllabus Overview and Weightage for 2026
For the 2025-26 academic session, the CBSE has maintained a focused approach. The unit "Dual Nature of Radiation and Matter" typically covers:
Photoelectric Effect: Hertz and Lenard's observations, Einstein's photoelectric equation, and the particle nature of light.
Experimental Study: Impact of intensity, potential, and frequency on photocurrent and stopping potential.
Matter Waves: de-Broglie relation and the wave nature of particles.
Component | Marks Distribution (Expected) |
Section A (MCQs/VSA) | 1 - 2 Marks |
Section B (Short Answer) | 2 Marks |
Section C (Case-Based/Long) | 3 - 4 Marks |
Total | 4 - 6 Marks |
Important Formula for Revision
To solve numerical problems effectively, students must memorize the core concepts. In the CBSE Class 12 Physics Question Bank 2026, the following formulas are highly repeated:
Energy of a Photon
Einstein’s Photoelectric Equation
Work Function and Threshold Frequency Relation
Stopping Potential and Maximum Kinetic Energy
De-Broglie Wavelength of a Particle
De-Broglie Wavelength of an Accelerated Electron
Momentum of a Photon
High-Probability Important Questions for 2026
Very Short Answer Questions (1 Mark)
Define the term "Work Function" for a metal.
Why are alkali metals preferred for photoelectric cells?
How does the stopping potential change if the distance between the source and the cell is doubled?
What is the rest mass of a photon?
Short Answer Questions (2 - 3 Marks)
The Frequency vs. Intensity Debate: Explain why the maximum kinetic energy of photoelectrons depends on the frequency of incident radiation but is independent of its intensity.
Einstein’s Equation Proof: List three features of the photoelectric effect that cannot be explained by the wave theory of light but are easily explained by Einstein's equation.
Numerical Challenge: Calculate the de-Broglie wavelength of an electron accelerated through a potential difference of 100V.
Case-Study Based Questions (4 Marks)
A scenario involving different metals (e.g., Sodium, Copper, Platinum) exposed to the same monochromatic light source. You will be asked to identify which metal will emit electrons based on their respective work functions.
Previous Year Paper Analysis (2018–2025)
Analyzing the last several years of papers reveals a pattern:
Graphs are Mandatory: Almost every year, a graph showing the variation of photocurrent with collector potential or stopping potential vs. frequency is asked.
Medical Relevance: Photoelectric cells are widely used in medical imaging and diagnostic tools. Understanding the "Electric Eye" concept is crucial for students aiming for healthcare careers.
Threshold Frequency: Many questions focus on the minimum frequency required to eject an electron, emphasizing that "Intensity" does not trigger emission if frequency is below the threshold.
Official Resources and Links
CBSE Official Academic Portal: cbseacademic.nic.in
Official Link : https://www.cbse.gov.in/cbsenew/question_bank.html
CBSE Academic Question Bank: Official CBSE Class 12 Materials
Conclusion
Preparing with a structured CBSE Class 12 Physics Question Bank 2026 is the most effective way to handle the pressure of board exams. By focusing on repeated PYQs, mastering the experimental graphs, and understanding the particle-wave duality, you ensure a strong performance. Stay updated with official notifications and keep practicing numericals to sharpen your speed.
FAQs on CBSE Class 12 Physics Question Bank 2026
Q1: How can I score full marks in the Dual Nature chapter using the CBSE Class 12 Physics Question Bank 2026?
A: Focus on the graphical representations and Einstein's Photoelectric Equation. Practice numericals related to the de-Broglie wavelength of electrons, as these are frequently repeated in the CBSE Class 12 Physics Question Bank 2026.
Q2: Is the Davison-Germer experiment included in the 2026 syllabus?
A: As per the latest updates, the experimental details of the Davisson-Germer experiment are often kept qualitative. Always refer to the latest NCERT and official circulars for any minor deletions.
Q3: What is the significance of the "Stopping Potential"?
A: Stopping potential is the negative potential applied to the anode at which the photoelectric current becomes zero. It is a direct measure of the maximum kinetic energy of the emitted electrons.
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