Chapter 9: Physical Optics - Key Topics MCQS
Chapter 9: Physical Optics - Key Topics
Below are 10 Multiple Choice Questions (MCQs) with answers and brief explanations, specifically from Chapter 9: Physical Optics of the FBISE (Federal Board of Intermediate and Secondary Education) 11th-class Physics syllabus for the 2025 exam. These MCQs are designed to align with the FBISE syllabus, focusing on key concepts such as wave nature of light, interference, diffraction, polarization, and Young’s double-slit experiment, as outlined in the official curriculum and reflected in past papers and resources like www.taleemcity.com and www.ilmistarsacademy.com. They are crafted to match the style and difficulty level of FBISE exams.
Chapter 9: Physical Optics - Key Topics
- Wave Nature of Light: Huygens’ principle, wavefronts.
- Interference: Constructive and destructive interference, Young’s double-slit experiment.
- Diffraction: Diffraction grating, single-slit diffraction.
- Polarization: Polarized light, applications.
- Applications: Thin films, optical phenomena (e.g., colors in soap bubbles).
10 MCQs with Answers and Explanations
- Question: The wave nature of light is demonstrated by:
- A) Reflection
- B) Refraction
- C) Interference
- D) Dispersion
- Answer: C) Interference
- Explanation: Interference, where light waves superpose to form patterns (e.g., in Young’s experiment), is a key evidence of light’s wave nature.
- Question: In Young’s double-slit experiment, constructive interference occurs when the path difference is:
- A) λ/2
- B) λ
- C) λ/4
- D) 3λ/2
- Answer: B) λ
- Explanation: Constructive interference occurs when the path difference is an integral multiple of the wavelength (nλ, where n = 0, 1, 2, …), with λ being a common case.
- Question: The fringe width in Young’s double-slit experiment is given by:
- A) β = λD/d
- B) β = λd/D
- C) β = Dd/λ
- D) β = λ/Dd
- Answer: A) β = λD/d
- Explanation: Fringe width β = λD/d, where λ is wavelength, D is the distance to the screen, and d is slit separation.
- Question: If the wavelength of light in Young’s experiment is increased, the fringe width:
- A) Decreases
- B) Increases
- C) Remains the same
- D) Becomes zero
- Answer: B) Increases
- Explanation: Fringe width β = λD/d. If wavelength λ increases, β increases proportionally.
- Question: Diffraction of light is most pronounced when the slit width is:
- A) Much larger than the wavelength
- B) Much smaller than the wavelength
- C) Comparable to the wavelength
- D) Equal to the frequency
- Answer: C) Comparable to the wavelength
- Explanation: Diffraction is significant when the slit width is on the order of the wavelength of light, causing noticeable bending.
- Question: The colors observed in a thin film (e.g., soap bubble) are due to:
- A) Diffraction
- B) Refraction
- C) Interference
- D) Polarization
- Answer: C) Interference
- Explanation: Colors in thin films result from the interference of light reflected from the top and bottom surfaces of the film.
- Question: In a diffraction grating, the condition for the first-order maximum is:
- A) d sinθ = λ
- B) d cosθ = λ
- C) d sinθ = 2λ
- D) d cosθ = 2λ
- Answer: A) d sinθ = λ
- Explanation: For a diffraction grating, the condition for maxima is d sinθ = mλ, where m = 1 for the first-order maximum.
- Question: Polarization of light is possible because light is a:
- A) Longitudinal wave
- B) Transverse wave
- C) Mechanical wave
- D) Stationary wave
- Answer: B) Transverse wave
- Explanation: Polarization occurs in transverse waves (like light), where the electric field oscillates in specific planes, unlike longitudinal waves.
- Question: Huygens’ principle is used to explain:
- A) Reflection and refraction
- B) Interference and diffraction
- C) Polarization and dispersion
- D) Both A and B
- Answer: D) Both A and B
- Explanation: Huygens’ principle, which states that every point on a wavefront acts as a source of secondary wavelets, explains reflection, refraction, interference, and diffraction.
- Question: In a single-slit diffraction pattern, the central maximum is:
- A) Narrower than subsidiary maxima
- B) Wider than subsidiary maxima
- C) Equal in width to subsidiary maxima
- D) Absent
- Answer: B) Wider than subsidiary maxima
- Explanation: In single-slit diffraction, the central maximum is wider and brighter than the narrower, dimmer subsidiary maxima.
Key Notes
- Syllabus Alignment: These MCQs cover core topics from Chapter 9 (Physical Optics) of the FBISE 11th-class Physics syllabus, including interference, diffraction, polarization, and Young’s experiment, which are frequently tested in exams.
- Question Variety: The questions include conceptual, theoretical, and formula-based MCQs to reflect FBISE’s exam pattern, with emphasis on optical phenomena and wave properties.
- Explanations: Brief explanations clarify the reasoning, aiding quick understanding and revision.
Recommended Resources for Additional MCQs
For more MCQs on Chapter 9 (Physical Optics):
- FBISE Official Website (www.fbise.edu.pk):
- Access past papers (2016–2024) under “Examinations” > “Past Papers.” Chapter 9 MCQs appear in the objective section.
- Taleem City (www.taleemcity.com):
- Offers solved MCQs for Chapter 9 in PDF format, tailored for FBISE syllabus.
- Ilmi Stars Academy (www.ilmistarsacademy.com):
- Provides chapter-specific MCQs with answers and video explanations.
- Download Class Notes (www.downloadclassnotes.com):
- Contains solved MCQs for Physical Optics in downloadable PDFs.
- Pak Learning Spot (www.paklearningspot.com):
- Features free MCQs for FBISE board exams, including Chapter 9.
How to Access:
- Visit these websites, navigate to the 11th-class Physics section, and select “Chapter 9 MCQs” or “Physical Optics.”
- Past papers are available on the FBISE website in PDF format, free of charge.
Tips for MCQ Preparation
- Focused Practice: Solve 10–15 MCQs daily for Chapter 9 to master concepts like interference and diffraction.
- Time Yourself: Aim for ~1 minute per MCQ to build exam speed.
- Review Errors: Use answer keys to understand mistakes and revisit concepts like Young’s experiment or polarization.
- Combine with Diagrams: Pair MCQ practice with studying diagrams (e.g., diffraction grating, thin film interference) from the FBISE textbook (available on www.taleem360.com).
Additional Support
These 10 MCQs are tailored to support your preparation for the 2025 FBISE exam. If you need:
- More MCQs for Chapter 9 (Physical Optics).
- MCQs for other chapters or specific topics (e.g., Young’s experiment, diffraction grating).
- Assistance downloading resources or solving numericals. please let me know, and I’ll provide further tailored support. Good luck with your Physics exam preparation!
Comments
Post a Comment