CBSE Board Exam 2025
Table of Contents
The CBSE (Central Board of Secondary Education) Board exams are one of the most crucial events in a student’s academic journey, and for students preparing for the Physics exam in 2025, having a clear understanding of the important topics and questions is vital for a high score. The sample papers provided by CBSE are a great resource to get familiar with the exam format and types of questions that may appear. Here is a breakdown of important questions and topics from the sample paper that are likely to help you prepare effectively.
1. Mechanics and Laws of Motion:
Mechanics is a core area in Physics that carries significant weight in the CBSE exam. Key questions from this unit can test your understanding of concepts like Newton’s Laws of Motion, work-energy theorem, friction, and circular motion.
Sample Questions:
- Define and explain Newton’s three laws of motion with examples.
- A block of mass ‘m’ is placed on a rough surface. Derive an expression for the force of friction acting on the block when a force is applied to it.
- A car accelerates uniformly from rest. Derive the equations of motion for its velocity and displacement.
- Discuss the concept of circular motion and derive an expression for the centripetal force.
Important Concepts to Revise:
- Newton’s Laws and their application
- Work-energy theorem
- Friction and its types (static and kinetic)
- Uniform circular motion, centripetal acceleration, and force
2. Kinematics:
Kinematics deals with the motion of objects without considering the forces involved. This is another important topic that forms the foundation for various real-life applications.
Sample Questions:
- A stone is thrown vertically upwards with an initial velocity ‘u’. Derive an expression for its maximum height and time of flight.
- What is the difference between uniform and non-uniform motion? Illustrate with examples.
- A body moves with a constant acceleration. If its velocity at time ‘t’ is ‘v’, derive an expression for the distance traveled in time ‘t’.
Important Concepts to Revise:
- Equations of motion for uniform acceleration
- Concept of velocity, displacement, and acceleration
- Graphical representation of motion
- Relative motion
3. Work, Energy, and Power:
This chapter is vital as it forms a significant part of the theoretical and numerical questions. Understanding the relationship between work, energy, and power is essential for scoring well.
Sample Questions:
- Define work and derive the SI unit of work. Also, explain the concept of positive and negative work.
- Derive the law of conservation of mechanical energy. Explain with an example.
- A body of mass ‘m’ is raised to a height ‘h’. Calculate the potential energy at this height and the work done in raising the body.
- Explain the concept of power and derive an expression for average power.
Important Concepts to Revise:
- Work-energy theorem
- Kinetic energy and potential energy
- Law of conservation of energy
- Power and its units
- Applications in real-life contexts (e.g., lifting, motion of objects)
4. Gravitation:
Gravitation, introduced through Newton’s law of universal gravitation, is another critical topic for the CBSE board exam. Students often encounter questions related to gravitational force, acceleration due to gravity, and satellite motion.
Sample Questions:
- State and explain the law of universal gravitation. Derive the expression for the gravitational force between two masses.
- Derive the expression for the acceleration due to gravity at the surface of the Earth.
- A satellite is orbiting the Earth at a certain height. Derive an expression for the orbital velocity and time period of the satellite.
- Explain the concept of escape velocity. Derive its expression.
Important Concepts to Revise:
- Newton’s law of gravitation and gravitational constant
- Acceleration due to gravity and its variation
- Gravitational potential energy
- Motion of satellites and escape velocity
5. Thermodynamics:
Thermodynamics is a critical chapter that focuses on the study of heat and work. Understanding concepts like laws of thermodynamics, heat engines, and efficiency is key for solving both theoretical and numerical problems.
Sample Questions:
- State and explain the first law of thermodynamics. Derive the relationship between heat, work, and internal energy.
- What is a Carnot engine? Derive an expression for its efficiency.
- Explain the concept of entropy and its significance in thermodynamic processes.
- Discuss the second law of thermodynamics and its applications.
Important Concepts to Revise:
- First law and second law of thermodynamics
- Heat and internal energy
- Carnot cycle and efficiency of heat engines
- Entropy and its implications
6. Electrostatics:
Electrostatics is an important section of Physics that deals with electric charges and fields. Questions based on Coulomb’s law, electric potential, and capacitors are often asked.
Sample Questions:
- State and explain Coulomb’s law in electrostatics. Derive the expression for the electrostatic force between two point charges.
- Derive an expression for the electric potential due to a point charge.
- Define capacitance and derive the expression for the capacitance of a parallel plate capacitor.
- Explain the concept of electric field lines and their properties.
Important Concepts to Revise:
- Coulomb’s law and electrostatic force
- Electric field and electric potential
- Capacitors and their combinations
7. Current Electricity:
Current electricity is one of the most practical chapters of Physics, where students learn about circuits, Ohm’s law, and electrical power. Understanding the relationship between voltage, current, and resistance is essential.
Sample Questions:
- State and explain Ohm’s law. Derive an expression for current in terms of potential difference and resistance.
- Derive an expression for the equivalent resistance in series and parallel combinations of resistors.
- What is electrical power? Derive an expression for electrical power in terms of current and voltage.
Important Concepts to Revise:
- Ohm’s law
- Series and parallel combination of resistors
- Electrical energy and power
- Kirchhoff’s laws
8. Magnetic Effects of Current and Magnetism:
This topic explores the relationship between electric currents and magnetic fields. Understanding how currents create magnetic fields and the forces between magnetic fields and current-carrying conductors is crucial.
Sample Questions:
- State Ampere’s law and explain its significance in calculating the magnetic field.
- Derive the expression for the magnetic field at the center of a circular loop carrying current.
- What is the force on a current-carrying conductor placed in a magnetic field?
Important Concepts to Revise:
- Magnetic fields and their properties
- Ampere’s law and Biot-Savart law
- Force on current-carrying conductors in magnetic fields
- Applications like electromagnets and motors
9. Optics:
Optics deals with the behavior of light. It’s essential to focus on reflection, refraction, and the lens formula, as well as optical instruments like microscopes and telescopes.
Sample Questions:
- Derive the mirror equation and explain its application in real-life scenarios.
- Explain the refraction of light through a prism and derive an expression for the angle of deviation.
- Discuss the working of a simple microscope and the magnifying power.
Important Concepts to Revise:
- Laws of reflection and refraction
- Lens and mirror formulae
- Optical instruments (microscope, telescope)
10. Modern Physics:
Modern physics includes concepts like photoelectric effect, dual nature of matter, and nuclear physics.
Sample Questions:
- Explain Einstein’s photoelectric equation. Discuss the experimental verification of the photoelectric effect.
- What is nuclear fission? Discuss the process with examples.
- Explain the concept of the wave-particle duality of matter.
Important Concepts to Revise:
- Photoelectric effect and its significance
- Atomic models (Bohr’s model)
- Nuclear reactions and fission
Conclusion:
Physics for the CBSE Board Exam 2025 covers a broad range of topics. By focusing on the key concepts, practicing numerical problems, and solving sample papers, students can boost their preparation. Regular revision and time management will play a critical role in achieving a high score in the exam. Make sure to understand the derivations, definitions, and key concepts, as they are frequently asked in both theoretical and practical forms in the exam.
