Test Bank For Physics for Scientists & Engineers with Modern Physics (Volume 3) 5th Edition (Global Edition) By Douglas C. Giancoli | All 33-42 Chapters Covered With Questions And Verified Solutions With Detailed Rationales And Case Studies.

Test Bank For Physics for Scientists & Engineers with Modern Physics (Volume 3) 5th
Edition (Global Edition) By Douglas C. Giancoli | All 33-42 Chapters Covered With
Questions And Verified Solutions With Detailed Rationales And Case Studies.

, TABLE OF CONTENT



VII. OPTICS


33.Wave Optics


34.Ray Optics


35.Optical Instruments


VIII. RELATIVITY AND QUANTUM PHYSICS


36.Relativity


37.The Foundations of Modern Physics


38.Quantization


39.Wave Functions and Uncertainty

40.One-Dimensional Quantum Mechanics


41.Atomic Physics


42.Nuclear Physics

,CHAPTER 33: WAVE OPTICS – STUDY RESOURCE
33.1 Multiple Choice Questions

1. In a Young's double-slit experiment, the slit separation is doubled while the wavelength of light
and the screen distance remain unchanged. What happens to the fringe spacing?

• A) It doubles

• B) It halves

• C) It quadruples

• D) It remains the same

Correct Answer: B
Explanation: Fringe spacing (β) = λL/d. If d (slit separation) doubles, β = λL/(2d), which is half the
original value.

• A is incorrect because increasing d decreases β, not increases it.

• C is incorrect because quadrupling would require d to be quartered.

• D is incorrect because β is inversely proportional to d, so it must change.



2. What is the path difference between two waves from coherent sources arriving at the third
bright fringe (m=3) in a double-slit experiment?

• A) 1.5λ

• B) 2λ

• C) 3λ

• D) 3.5λ

Correct Answer: C
Explanation: For constructive interference (bright fringes), path difference = mλ, where m = 0, 1, 2,
3... For m=3, path difference = 3λ.

• A is incorrect (1.5λ gives destructive for m=1.5, not a bright fringe).

• B is incorrect (2λ corresponds to m=2).

• D is incorrect (3.5λ gives destructive interference).



3. In a single-slit diffraction experiment, the central maximum is widened when:

• A) The slit width is increased

• B) The wavelength is decreased

• C) The slit width is decreased

• D) The screen is moved closer

, Correct Answer: C
Explanation: The angular width of the central maximum is given by θ ≈ λ/a. Decreasing slit width (a)
increases θ, widening the central maximum.

• A is incorrect because increasing a narrows the central maximum.

• B is incorrect because decreasing λ narrows it.

• D is incorrect because moving the screen closer reduces the physical width on the screen,
though angular width remains unchanged.



4. A diffraction grating has 5000 lines/cm. What is the grating spacing (d)?

• A) 2.0 × 10⁻⁶ m

• B) 2.0 × 10⁻⁴ m

• C) 5.0 × 10⁻⁶ m

• D) 5.0 × 10⁻⁴ m

Correct Answer: A
Explanation: d = 1/(lines per meter) = 1/(5000 lines/cm × 100 cm/m) = 1/(5.0 × 10⁵) = 2.0 × 10⁻⁶ m.

• B is incorrect (this would be for 5000 lines/m, not cm).

• C is incorrect (this would be for 2000 lines/cm).

• D is incorrect (this is for 2000 lines/m).



5. For a diffraction grating, the condition for constructive interference is:

• A) d sin θ = (m + ½)λ

• B) d sin θ = mλ

• C) a sin θ = mλ

• D) d sin θ = mλ/2

Correct Answer: B
Explanation: For a grating, bright maxima occur when d sin θ = mλ, where m = 0, ±1, ±2, ... (same as
double-slit but with sharper peaks).

• A is incorrect – this is the condition for destructive interference in double-slit or thin films.

• C is incorrect – this is the single-slit diffraction minima condition (with a = slit width).

• D is incorrect – this would give half-integer multiples, which is not correct for gratings.



6. In a thin film interference scenario (soap film in air), a film appears blue in reflected light. If the
film thickness increases slightly, the reflected color would most likely: