Chapter 12: Diffraction

12.1 Diffraction from a Single Slit

12.2 Diffraction Grating

12.3 Resolving Power of Optical Instruments

Important Short Questions and Answers in Short

Q1. Define diffraction.
👉 Bending of light around edges or through narrow slits.

Q2. Condition for minima in single slit?

👉 asinθ=nλ

Q3. Formula for angular width of central maximum?

👉 Δθ=2λ/a

Q4. Condition for maxima in diffraction grating?

👉 dsinθ=nλ

Q5. What is resolving power?
👉 Ability to distinguish two close wavelengths R=λ/Δλ

Q6. Resolving power of grating?

👉 R=nN

✅ Formula Sheet (Quick Revision)

Numerical Examples