Competency-Based MCQs Class 12 Physics
Competency-Based MCQs Class 12 Physics – Experimental Skills
Class: 12
Subject: Physics
Section: 10 – Experimental Skills
Topic: Competency-Based MCQs
Board: CBSE Board Examinations
Subject: Physics
Section: 10 – Experimental Skills
Topic: Competency-Based MCQs
Board: CBSE Board Examinations
Instructions: These Multiple Choice Questions (MCQs) are designed strictly as per the NCERT syllabus, making them ideal for CBSE Class 12 Board Examination standards. Each question tests experimental understanding, observation skills, and data interpretation ability.
1. In a meter bridge experiment, the null point is obtained at the center. This indicates:
Answer: A
Explanation: Null point at 50 cm means bridge is balanced with equal ratio arms. Hence both resistances are equal.
Explanation: Null point at 50 cm means bridge is balanced with equal ratio arms. Hence both resistances are equal.
2. Least count of a screw gauge depends on:
Answer: C
Explanation: Least count = Pitch ÷ Number of circular scale divisions.
Explanation: Least count = Pitch ÷ Number of circular scale divisions.
3. Zero error in vernier calipers is corrected by:
Answer: B
Explanation: Observed reading is corrected by subtracting zero error.
Explanation: Observed reading is corrected by subtracting zero error.
4. In Ohm’s law experiment, slope of V–I graph gives:
Answer: B
Explanation: From V = IR, slope (V/I) = Resistance.
Explanation: From V = IR, slope (V/I) = Resistance.
5. Parallax error occurs when:
Answer: B
Explanation: Eye must be vertically above scale to avoid parallax.
Explanation: Eye must be vertically above scale to avoid parallax.
6. Unit of resistivity measured experimentally is:
Answer: B
Explanation: Resistivity ρ = RA/L → unit Ω m.
Explanation: Resistivity ρ = RA/L → unit Ω m.
7. Slope of stopping potential vs frequency graph gives:
Answer: B
Explanation: From photoelectric equation slope = h/e.
Explanation: From photoelectric equation slope = h/e.
8. Ammeter is connected:
Answer: B
Explanation: To measure current, ammeter is placed in series.
Explanation: To measure current, ammeter is placed in series.
9. Voltmeter resistance should be:
Answer: A
Explanation: High resistance ensures negligible current draw.
Explanation: High resistance ensures negligible current draw.
10. Error due to instrument defect is:
Answer: B
Explanation: Instrumental errors are systematic.
Explanation: Instrumental errors are systematic.
11. Least count of meter scale is usually:
Answer: B
Explanation: Smallest division is 1 mm.
Explanation: Smallest division is 1 mm.
12. Intercept of V–I graph (non‑ohmic) shows:
Answer: B
Explanation: Non‑zero intercept indicates internal emf/contact effects.
Explanation: Non‑zero intercept indicates internal emf/contact effects.
13. Magnifying power of simple microscope increases with:
Answer: B
Explanation: M ∝ 1/f.
Explanation: M ∝ 1/f.
14. Graph between frequency and wavelength is:
Answer: B
Explanation: c = νλ → inverse relation.
Explanation: c = νλ → inverse relation.
15. Which instrument measures emf accurately?
Answer: C
Explanation: Potentiometer uses null method → most accurate.
Explanation: Potentiometer uses null method → most accurate.
16. In potentiometer, longer wire means:
Answer: B
Explanation: Potential gradient decreases → precision increases.
Explanation: Potential gradient decreases → precision increases.
17. Random errors are reduced by:
Answer: B
Explanation: Mean value minimizes random fluctuations.
Explanation: Mean value minimizes random fluctuations.
18. SI unit of experimental error is:
Answer: A
Explanation: Error carries same unit as measurement.
Explanation: Error carries same unit as measurement.
19. A straight line graph indicates:
Answer: B
Explanation: Straight line through origin → proportional relation.
Explanation: Straight line through origin → proportional relation.
20. Significant figures indicate:
Answer: A
Explanation: More significant figures → higher measurement accuracy.
Explanation: More significant figures → higher measurement accuracy.
