MCQS work and energy
Below are 10 Multiple Choice Questions (MCQs) with answers and brief explanations, specifically from Chapter 4: Work and Energy 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 work, kinetic and potential energy, conservation of energy, power, and work-energy theorem, 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 4: Work and Energy - Key Topics
- Work: Definition, work done by constant and variable forces, work as a scalar product.
- Energy: Kinetic energy, potential energy (gravitational), work-energy theorem.
- Conservation of Energy: Mechanical energy conservation.
- Power: Rate of doing work, units (watt).
- Applications: Real-world scenarios (e.g., lifting objects, machines).
10 MCQs with Answers and Explanations
- Question: Work done by a force is maximum when the angle between force and displacement is:
- A) 0°
- B) 45°
- C) 90°
- D) 180°
- Answer: A) 0°
- Explanation: Work W = F × d × cosθ. It is maximum when cosθ = 1, i.e., θ = 0° (force and displacement in the same direction).
- Question: A 2 kg object moves at 3 m/s. Its kinetic energy is:
- A) 6 J
- B) 9 J
- C) 12 J
- D) 18 J
- Answer: B) 9 J
- Explanation: Kinetic energy K = (1/2)mv² = (1/2) × 2 × 3² = 1 × 9 = 9 J.
- Question: A body of mass 5 kg is lifted 10 m vertically. The potential energy gained (g = 10 m/s²) is:
- A) 50 J
- B) 100 J
- C) 250 J
- D) 500 J
- Answer: D) 500 J
- Explanation: Potential energy U = mgh = 5 × 10 × 10 = 500 J.
- Question: The work-energy theorem states that the work done by the net force is equal to:
- A) Change in potential energy
- B) Change in kinetic energy
- C) Change in momentum
- D) Change in power
- Answer: B) Change in kinetic energy
- Explanation: The work-energy theorem states W_net = ΔK = (1/2)mv²_final - (1/2)mv²_initial.
- Question: A machine does 2000 J of work in 10 seconds. The power delivered is:
- A) 20 W
- B) 100 W
- C) 200 W
- D) 2000 W
- Answer: C) 200 W
- Explanation: Power P = Work/time = 2000/10 = 200 W (watt = J/s).
- Question: If the speed of an object doubles, its kinetic energy:
- A) Doubles
- B) Halves
- C) Quadruples
- D) Remains the same
- Answer: C) Quadruples
- Explanation: Kinetic energy K = (1/2)mv². If v doubles, K becomes (1/2)m(2v)² = 4 × (1/2)mv² = 4K.
- Question: The unit of work in SI is equivalent to:
- A) Newton-meter
- B) Joule
- C) Watt
- D) Both A and B
- Answer: D) Both A and B
- Explanation: Work = force × distance = N × m = joule (J). Thus, both newton-meter and joule are correct.
- Question: A body falls freely from a height h. At the ground, its potential energy is:
- A) Maximum
- B) Zero
- C) Equal to kinetic energy
- D) Half of initial potential energy
- Answer: B) Zero
- Explanation: At the ground (h = 0), potential energy U = mgh = 0, as all potential energy converts to kinetic energy (ignoring air resistance).
- Question: In an isolated system, the total mechanical energy is conserved if:
- A) Only conservative forces act
- B) Only non-conservative forces act
- C) Friction is present
- D) External forces act
- Answer: A) Only conservative forces act
- Explanation: Mechanical energy (K + U) is conserved when only conservative forces (e.g., gravity) act, with no work done by non-conservative forces like friction.
- Question: A force of 20 N moves an object 5 m at an angle of 60° to the displacement. The work done is:
- A) 50 J
- B) 100 J
- C) 200 J
- D) 500 J
- Answer: A) 50 J
- Explanation: Work W = F × d × cosθ = 20 × 5 × cos60° = 100 × 0.5 = 50 J.
Key Notes
- Syllabus Alignment: These MCQs cover core topics from Chapter 4 (Work and Energy) of the FBISE 11th-class Physics syllabus, including work, kinetic and potential energy, conservation of energy, and power, which are high-weightage topics in exams.
- Question Variety: The questions include conceptual, numerical, and application-based MCQs to reflect FBISE’s exam pattern, with emphasis on energy calculations and theorems.
- Explanations: Brief explanations clarify the reasoning, aiding quick understanding and revision.
Recommended Resources for Additional MCQs
For more MCQs on Chapter 4 (Work and Energy):
- FBISE Official Website (www.fbise.edu.pk):
- Access past papers (2016–2024) under “Examinations” > “Past Papers.” Chapter 4 MCQs are common in the objective section.
- Taleem City (www.taleemcity.com):
- Offers solved MCQs for Chapter 4 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 Work and Energy in downloadable PDFs.
- Pak Learning Spot (www.paklearningspot.com):
- Features free MCQs for FBISE board exams, including Chapter 4.
How to Access:
- Visit these websites, navigate to the 11th-class Physics section, and select “Chapter 4 MCQs” or “Work and Energy.”
- 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 4 to master concepts like energy conservation and power calculations.
- Time Yourself: Aim for ~1 minute per MCQ to build exam speed.
- Review Errors: Use answer keys to understand mistakes and revisit concepts like the work-energy theorem.
- Combine with Numericals: Pair MCQ practice with numerical problems (e.g., work done, energy transformations) 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 4 (Work and Energy).
- MCQs for other chapters or specific topics (e.g., conservation of energy, power).
- Assistance downloading resources or solving numericals. please let me know, and I’ll provide further tailored support. Good luck with your Physics exam preparation!
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