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CBSE Class 11 Physics Chapter 6 Work, Energy and Power MCQ
Class 11 Physics Chapter 6 focuses on Work, Energy, and Power, essential concepts in understanding the mechanics of solids. This chapter is crucial as it lays the foundation for various physical phenomena and principles that students will encounter in higher studies.
To aid in mastering these concepts, a comprehensive set of MCQs (Multiple Choice Questions) has been developed. These class 11 physics mcqs questions are tailored to align with the latest CBSE syllabus and NCERT guidelines, ensuring that students are well-prepared for their examinations. The Work, Energy, and Power MCQ collection serves as an effective tool for self-assessment and revision.
Students can access a Work, Energy, and Power Class 11 MCQ PDF to facilitate their study sessions. This resource not only includes a variety of questions but also provides answers, allowing learners to evaluate their understanding of the subject matter. Additionally, the mechanics of solids MCQ with answers PDF is available for those who wish to delve deeper into specific topics within this chapter.
For those looking to practice extensively, the work, energy, and power MCQ questions are designed to cover all critical aspects of the chapter. Students can also find options for work, energy, and power MCQ PDF download to ensure they have offline access to these valuable resources.
By engaging with these MCQs, students can enhance their grasp of key concepts such as the work-energy theorem, kinetic energy, potential energy, and power. This preparation is vital not just for scoring well in exams but also for developing a robust understanding of physics that will benefit them in future studies.
Class 11 Physics Work, Energy and Power Overview
Here’s an overview of the Work, Energy, and Power chapter for Class 11 Physics:
1. Work
Definition: Work is done when a force acting on an object causes a displacement of the object in the direction of the force.
Mathematical Representation: Work (W) = Force (F) × Displacement (s) × cos(θ), where θ is the angle between the force vector and the displacement vector.
Units: Joule (J)
Types of Work:
- Positive Work: When the force and displacement are in the same direction.
- Negative Work: When the force and displacement are in opposite directions.
- Zero Work: When the force is perpendicular to the displacement or there is no displacement.
2. Energy
Definition: Energy is the capacity to do work.
Types of Energy:
- Kinetic Energy: The energy possessed by an object due to its motion.
- Formula: KE = (1/2)mv², where m is the mass and v is the velocity.
- Potential Energy: The energy possessed by an object due to its position or configuration.
- Gravitational Potential Energy: PE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height.
- Elastic Potential Energy: PE = (1/2)kx², where k is the spring constant and x is the displacement from the equilibrium position.
- Other forms of energy: Chemical energy, thermal energy, electrical energy, nuclear energy, etc.
3. Power
- Definition: Power is the rate of doing work or the rate at which energy is transferred.
- Mathematical Representation: Power (P) = Work (W) / Time (t) or Power (P) = Force (F) × Velocity (v)
- Units: Watt (W)
Key Concepts
- Work-Energy Theorem: The work done on an object is equal to the change in its kinetic energy.
- Conservation of Mechanical Energy: In the absence of non-conservative forces (like friction), the total mechanical energy (kinetic energy + potential energy) of a system remains constant.
- Conservative and Non-Conservative Forces: Conservative forces (like gravity) do not depend on the path taken, while non-conservative forces (like friction) depend on the path taken.
This overview should provide a good foundation for understanding the key concepts in the Work, Energy, and Power chapter. Now you can proceed with the practice MCQs.
Class 11 Physics Work, Energy and Power MCQ Questions and Answers
Question 1: No work is done if:
(a) Displacement is zero
(b) Force is zero
(c) Force and displacement are mutually perpendicular
(d) All of the above
Answer: (d) All of the above
Explanation: Work is done when a force causes displacement. If the displacement is zero, if the force is zero, or if the force is perpendicular to the displacement (i.e., no component of force in the direction of displacement), no work is d
Question 2: Which is the type of collision in which both the linear momentum and the kinetic energy of the system remain conserved?
(a) Inelastic Collision
(b) Elastic Collision
(c) Destructive collision
(d) None of the options
Answer: (b) Elastic Collision
Explanation: In an elastic collision, both linear momentum and kinetic energy are conserved. In inelastic collisions, only momentum is conserved, while kinetic energy is not.
Question 3: Find the potential energy stored in a ball of mass 5 kg placed at a height of 3 m above the ground.
(a) 121 J
(b) 147 J
(c) 227 J
(d) 182 J
Answer: (b) 147 J
Explanation:The potential energy is calculated by the formula PE = mgh, where m = 5 kg, g = 9.8 m/s², and h = 3 m. Therefore, PE = 5 × 9.8 × 3 = 147 J.
Question 4: An electric heater of rating 1000 W is used for 5 hours per day for 20 days. What is the electrical energy utilized?
(a) 100 kWh
(b) 200 kWh
(c) 120 kWh
(d) 500 kWh
Answer: (a) 100 kWh
Explanation: The energy utilized is Power × Time = 1000 W × 5 hrs/day × 20 days = 100,000 Wh = 100 kWh.
Question 5: The rate of doing work is called:
(a) Force
(b) Acceleration
(c) Power
(d) Displacement
Answer: (c) Power
Explanation:Power is the rate at which work is done, and it is defined as P = W / t, where W is the work done and t is the time taken.
Question 6: A ball moves in a frictionless inclined table without slipping. The work done by the table surface on the ball is:
(a) Negative
(b) Zero
(c) Positive
(d) None of the options
Answer: (b) Zero
Explanation: In the case of frictionless motion, no work is done by the table because the ball doesn’t experience any force in the direction of its motion (other than the normal force, which does no work).
Question 7: The potential energy of a system increases if work is done:
(a) Upon the system by a non-conservative force
(b) By the system against a conservative force
(c) By the system against a non-conservative force
(d) Upon the system by a conservative force
Answer: (b) By the system against a conservative force
Explanation: When work is done by the system against a conservative force (like gravity), the potential energy of the system increases.
Question 8: If a light body and a heavy body have the same kinetic energy, then which one has greater linear momentum?
(a) Lighter body
(b) Heavier body
(c) Both have the same momentum
(d) Can’t be predicted
Answer: (b) Heavier body
Explanation: Since kinetic energy (KE) is given by the formula KE = 1/2 m v², and momentum (p) is given by p = mv, for equal kinetic energies, the heavier body will have a greater momentum due to its larger mass.
Question 9: A light and a heavy body have equal momentum. Which one has greater K.E.?
(a) The lighter body
(b) The heavier body
(c) Both have equal K.E.
(d) Data given is incomplete
Answer: (a) The lighter body
Explanation: Kinetic energy is proportional to the square of velocity. For the same momentum, the lighter body will have a higher velocity and thus greater kinetic energy.
Question 10: Unit of energy is:
(a) kWh
(b) Joule
(c) Electron volt
(d) All of the above
Answer: (d) All of the above
Explanation: Energy can be measured in various units: kilowatt-hours (kWh), joules (J), and electron volts (eV) are all commonly used units.
Question 11: Which of the following is not a conservative force?
(a) Gravitational force
(b) Frictional force
(c) Spring force
(d) None of these
Answer: (b) Frictional force
Explanation: Conservative forces (such as gravity and spring force) do not depend on the path taken, while non-conservative forces (such as friction) do.
Question 12: The speed of an object of mass m dropped from an inclined plane (frictionless), at the bottom of the plane, depends on:
(a) Height of the plane above the ground
(b) Angle of inclination of the plane
(c) Mass of the object
(d) All of these
Answer: (a) Height of the plane above the ground
Explanation: The speed of the object depends on the potential energy converted into kinetic energy, which only depends on the height of the object, not its mass or the angle of inclination (in a frictionless environment).
Question 13: A body projected vertically from the earth reaches a height equal to earth’s radius before returning to the earth. The power exerted by the gravitational force is greatest:
(a) At the instant just before the body hits the earth
(b) At the highest position of the body
(c) It remains constant all through
(d) At the instant just after the body is projected
Answer: (a) At the instant just before the body hits the earth
Explanation: The power exerted by gravitational force is greatest when the speed is highest, which is just before impact.
Question 14: If two particles are brought near one another, the potential energy of the system will:
(a) Increase
(b) Decrease
(c) Remain the same
(d) Equal to the K.E.
Answer: (a) Increase
Explanation: When two particles are brought closer in a system where attractive forces exist (like gravitational or electrostatic forces), the potential energy increases as they move toward each other.
Question 15: When two spheres of equal masses undergo a perfect inelastic collision with one of them at rest, after the collision they will move:
(a) Opposite to one another
(b) In the same direction
(c) Together
(d) At right angle to each other
Answer: (c) Together
Explanation: In a perfectly inelastic collision, the two bodies stick together after the collision, moving as a single object.
FAQs on Work, Energy and Power MCQ Class 11 Physics
What is the significance of the Work, Energy, and Power chapter in Class 11 Physics?
This chapter is crucial as it introduces fundamental concepts that explain how forces interact with objects, laying the groundwork for advanced physics topics.
How can practicing MCQs improve my understanding of Work, Energy, and Power?
Practicing MCQs helps reinforce key concepts, enhances problem-solving skills, and prepares students for exams by familiarizing them with the question format.
Are the MCQs aligned with the CBSE syllabus?
Yes, the MCQs are specifically designed to align with the latest CBSE syllabus and NCERT curriculum, ensuring comprehensive coverage of essential topics.
What types of questions can I expect in the Work, Energy, and Power MCQs?
The MCQs include questions on definitions, formulas, applications of work-energy theorem, calculations involving kinetic and potential energy, and power-related problems.
