100 Most Expected Physics Questions for Class 12 ⚡ | Score 90%+ in Boards 2026 By Akshay Sir

Class Overview and Upcoming Schedule

Introduction to Class Structure

• The instructor emphasizes the importance of student effort in today's class, indicating that regular attendees are likely familiar with the session's content.

• A recap of previous classes is provided, highlighting key topics covered on specific dates, including derivations and complete physics revisions.

Key Concepts and Engagement

• The instructor encourages students to engage actively by recalling important self-important questions discussed in class.

• Students are reminded that they will be solving questions together, with a focus on understanding concepts rather than just finding answers.

Upcoming Topics and Practice Sessions

• An outline of future classes is shared, including sample paper discussions and theoretical question marathons scheduled for specific dates.

• Emphasis is placed on practicing numerical problems independently to build confidence before upcoming assessments.

Class Participation Guidelines

Importance of Active Participation

• Students are encouraged to take notes during the live session and not worry about falling behind; active participation is crucial for learning.

• The instructor assures students that they will receive ample practice material through a Telegram group for further study.

Question Solving Approach

• A mix of question types (MCQs, long-form questions, theoretical questions) will be included in today’s class.

• Students should pause the video when instructed to solve questions independently before checking their answers later.

Detailed Problem-Solving Session

Initial Questions and Concepts

• The first question involves deriving expressions related to parallel circuits; students are prompted to solve it independently before moving forward.

Advanced Physics Concepts

• Discussion shifts towards velocity concepts, specifically differentiating between proper velocity and drift velocity within copper wires.

Particle Physics Insights

• The instructor explains relationships between protons, deuterons, and alpha particles regarding mass ratios and charge similarities while introducing kinetic energy formulas relevant for uniform magnetic fields.

Understanding Kinetic Energy and Magnetic Fields

Kinetic Energy and Radius Formula

• The radius of the path described by a neutron and alpha particle is given by the formula R = MV/QB .

• Kinetic energy is defined as KE = 1/2 mv^2 , prompting students to relate these concepts.

Current-Carrying Wire and Magnetic Field

• A straight wire (AB) carries a current of 4 Amperes, creating a magnetic field that exerts force on a nearby charge.

• Students are tasked with calculating the force exerted on a proton due to this magnetic field, including its direction.

Valentine's Day Reflections in Physics Class

Personal Anecdotes During Learning

• The instructor humorously questions why students did not celebrate Valentine's Day, sharing their own focus on education instead.

• Mention of February 14 being both Valentine’s Day and Martyrs' Day highlights cultural context while engaging students.

Electric Field Calculations

Net Electric Field from Charge Density

• Students are asked to calculate the net electric field resulting from two wires with given charge densities.

• Options for answers are provided, encouraging problem-solving skills.

Magnetic Fields and Circular Motion

Relationship Between Particles in Magnetic Fields

• Discussion about protons and alpha particles entering a magnetic field with equal velocities suggests they may have the same kinetic energy.

• Students must derive the ratio of radii for circular paths taken by these particles in the magnetic field.

Problem-Solving Approach Encouragement

Active Participation in Learning

• The instructor encourages students to pause, try solving problems independently, and engage actively during lessons.

• Emphasis on building confidence through practice rather than relying solely on teacher-led solutions.

Internal Resistance Calculation

Understanding Voltage and Current Relationships

• A question regarding internal resistance involves voltage and current values provided for analysis.

• Students need to apply knowledge of electric fields and potentials using E = -dv/dr .

Mass Number Ratios in Physics Problems

Exploring Mass Numbers A & B

• The mass numbers for two elements (A & B) are discussed, prompting calculations related to their ratios.

Prism Questions Related to Light Behavior

Critical Angles in Optics

• Discussion revolves around light incident normally on a prism face; understanding critical angles at glass-air interfaces is essential.

Extrinsic Semiconductors Explained

Doping Germanium with Boron

• Explanation of doping germanium crystals with boron introduces concepts of extrinsic semiconductors.

Electromagnetic Wave Propagation Directions

Directional Analysis of Electromagnetic Waves

• The question focuses on describing directions of electric fields associated with electromagnetic waves propagating northward.

Battery Supply Problem Solving Techniques

Analyzing Currents Through Resistors

• A scenario involving battery supply currents through different resistors prompts calculation of internal resistance based on varying conditions.

Deriving Expressions for Electric Current

Defining 1 Ampere Current

• The discussion begins with the definition of 1 Ampere current, emphasizing its frequent appearance in examinations.

• Two parallel wires are introduced, and the forces of attraction or repulsion between them due to current flow are highlighted.

• An equation is mentioned that needs to be derived to calculate the force acting on these wires.

Transformer Input Calculations

• A scenario involving a step-down transformer is presented, where input voltage and efficiency are given.

• The task is to determine the input current based on provided parameters like power and voltage.

Electric Field from Point Charges

• The problem involves two point charges placed 30 cm apart, with a +1 microcoulomb charge needing placement for zero net electric field.

• Following this, definitions related to drift velocity and equations involving current density and relaxation time are discussed.

Magnetic Field in Uniform Fields

• Discussion shifts towards uniform magnetic fields affecting materials A and B, focusing on their susceptibility.

• Participants are prompted to identify which material's susceptibility is being referred to.

Light Source and Spherical Formula Application

Light Source Positioning

• A point source of light located 12 cm away from a convex glass surface requires application of spherical formulas for calculations.

• The formula n_2/v - n_1/u = n_2 - n_1/r is emphasized as crucial for solving related problems.

Kinetic Energy Calculation

• Participants need to find stopping potential (EV), using values such as HC over wavelength (λ), where HC equals 1240 eV·nm.

Electric Flux and Kirchhoff's Laws

Electric Flux through Surfaces

• An electric square surface with side L meters prompts questions about calculating electric flux limited to its lower half.

Applying Kirchhoff’s Laws

• Emphasis on applying Kirchhoff's laws across three loops in an electrical circuit; participants must calculate currents in various wires labeled mn, pt, and sp.

Resonant Frequency Adjustments

Inductance Changes for Resonance

• Discussion revolves around maintaining resonant frequency while changing inductance within an LC circuit setup.

Energy Requirements for Electron Release

Minimum Energy Calculation

• Participants need to derive expressions regarding minimum energy required to free an electron from its ground state.

Electrostatic Potential in Charge Configurations

Charge Distribution Analysis

• A solid glass sphere scenario requires application of spherical formulas again; participants must find apparent positions of bubbles formed by light refraction.

Magnetic Field Calculations

Magnetic Field Contributions

• Discusses how different configurations contribute to total magnetic field at specific points; includes scenarios involving half-wires.

Dynamic Resistance Concepts

Forward Bias Diagrams

• Explains forward bias diagrams showing majority vs minority charge carriers along with dynamic resistance concepts relevant in semiconductor physics.

Self-Inductance Queries

Self-Inductance Comparisons

• Questions focus on comparing self-inductances between coils while determining equivalent capacitance across circuits containing multiple components.

Work Done Against Electrostatic Forces

Work Done Calculation

• Involves calculating work done when moving charges around a circular path influenced by electrostatic potentials among three point charges arranged triangularly.

Discussion on Electric Fields and Related Concepts

Introduction to Topics

• The speaker initiates a discussion about providing examples of para-dielectric and ferromagnetic materials, indicating the need for clarity in understanding these concepts.

• Acknowledges previous video content shared with students, including important topics, definitions, laws, derivations, and competency-based questions.

Review of Previous Content

• Encourages students to explore past videos from the channel for better preparation; emphasizes that many resources have already been provided.

• Introduces a challenging question regarding electric fields at an equatorial point of a dipole and discusses ideal dipole situations.

Problem-Solving Approach

• Discusses current sensitivity and voltage sensitivity in relation to increasing current sensitivity; encourages students to try solving related problems.

• Presents a question involving EMF calculation through differentiation and applying specific time values for solutions.

Complex Questions in Physics

Charge Systems Analysis

• Describes a scenario with three charges (two positive and one negative), asking students to determine potential energy within an equilateral triangle configuration.

Wave Properties Discussion

• Explains relationships between wavelengths of electrons, protons, and deuterons moving at the same speed; hints at using the formula λ = h/mv for calculations.

Practical Applications in Physics

Galvanometer Functionality

• Discusses how to convert a moving coil galvanometer into a voltmeter by analyzing its deflection based on given resistance and current values.

Astronomical Telescope Mechanics

• Outlines steps needed to calculate image formation when an astronomical telescope is set up at infinity; includes focal lengths of objective lenses.

Motivation and Dedication in Learning

Student Engagement Insights

• The speaker expresses intent to meet students post-exams while emphasizing the importance of dedication during live sessions for effective learning.

Differentiating Students' Mindsets

• Highlights differences between dedicated students who actively engage versus those who seek shortcuts without genuine effort.

Conclusion: Importance of Active Participation

Commitment to Learning

• Stresses that true commitment separates top performers from average ones; encourages continuous engagement with material rather than passive consumption.

Final Thoughts on Class Dynamics

• Concludes by asserting that today's class will significantly impact student motivation towards achieving high exam scores.

Thinking and Problem Solving in Physics

Importance of Reflection Before Answering Questions

• The speaker encourages participants to pause and think about the questions presented, emphasizing that even a few minutes of contemplation can be beneficial.

• Acknowledges the motivation derived from participant engagement, suggesting that positive feedback (like hearts) boosts morale for both students and the instructor.

Class Structure and Content

• The session is structured around numerical problems, with an emphasis on practical application over theoretical discussions.

• Introduces a question related to magnetic fields in circular loops, highlighting its relevance to previous topics covered in class.

Key Concepts in Electromagnetism

• Discusses work done on point charges arranged in an equilateral triangle, linking it to past exam questions.

• Explains the challenge of sourcing quality physics questions for practice, indicating their importance for student preparation.

Advanced Topics in Inductance and Optics

• Mentions mutual inductance between solenoids and verification of Snell's law through ray diagrams.

• Discusses convex mirrors' formulas for virtual image production as part of optics education.

Charge Interaction Problems

• Presents a scenario involving two positive ions separated by distance 'd', asking about the force of repulsion between them.

• Introduces a problem regarding charge transfer between two charges and its effect on force calculations.

Practical Applications in Circuit Theory

• Outlines tasks involving capacitors connected in series and parallel configurations, focusing on energy storage calculations.

• Describes electron behavior within magnetic fields, including linear distance traveled during circular motion.

Understanding Electric Fields and Impedance

• Discusses electric field distributions and asks participants to identify positive versus negative charges based on given conditions.

• Covers concepts like stopping potential related to photons impacting surfaces, leading into discussions about galvanometers converting into voltmeters.

This structured approach provides clarity on key topics discussed during the session while allowing easy navigation through timestamps for further exploration.

Nuclear Fusion and Energy Release

Understanding Nuclear Density

• Discussion on nuclear fusion, emphasizing the amount of energy released during the process.

• Inquiry into whether nuclear density is independent of mass number, referencing a previously derived formula.

Capacitors and Dielectrics

• Explanation of a parallel plate capacitor with area A and separation D, including the application of series and parallel formulas.

• Mention of dielectrics in capacitors and their effects on induced EMF current.

Optics and Microscopy

Relationship Between Microscopes and Telescopes

• Comparison between astronomical telescopes (with large objectives) and compound microscopes (with inverted objectives).

Current Flow in Wires

• Problem posed regarding an 8 mA current flowing through a wire, asking for the number of electrons passing through.

AC Circuits and Resonance

Impedance in LC Circuits

• Task to create a phasor diagram to illustrate impedance in an RLC circuit with given AC voltage frequency.

Application of Kirchhoff's Laws

• Instruction to apply Kirchhoff's laws to find solutions related to circuit problems involving spherical convex surfaces.

Electric Potential Energy Calculations

Alpha Particle Kinetic Energy

• Discussion about alpha particles' kinetic energy concerning atomic nuclei, focusing on calculating distances based on Rutherford's model.

Wheatstone Bridge Questions

Formation of Depletion Layers

• Examination of questions related to Wheatstone bridges, depletion layers, potential barriers, and their applications in rectifiers.

Cell Connections in Circuits

Parallel Cell Configuration

• Query regarding two cells connected in parallel with specified EMFs and internal resistances; calculation for final EMF required.

Induced Charge Calculation

• Problem-solving task focused on finding differences between EMF values and terminal voltages across two cells.

Young’s Double Slit Experiment Insights

Wave Interference Patterns

• Analysis involving intensity calculations at specific points where path difference is λ/8; emphasis on understanding wave interference principles.

Sample Paper Preparation

Mock Test Strategy

• Announcement about upcoming sample paper sessions designed as mock tests for students; focus on collaborative problem-solving during class time.

This structured markdown file captures key discussions from the transcript while providing timestamps for easy reference. Each section highlights important concepts relevant to physics topics discussed throughout the session.

Magnetic and Electric Concepts in Physics

Understanding Charge and Nuclear Radius

• Discussion on changing parameters related to charge q placed at the center of a cube, with emphasis on calculating flux through one face.

• Mention of nuclear radius for copper given as 3.6 femtometers, highlighting its significance in calculations.

Magnetic Susceptibility and Circuit Analysis

• Inquiry into the nature of magnetic susceptibility in materials, indicating its relevance in understanding material properties.

• Instructions to explain the working of a generator thoroughly, suggesting an exam-like preparation approach.

Capacitors and Voltage Calculations

• Reference to five capacitors connected between points P and Q, prompting calculation of capacitance.

• Emphasis on RMS voltage across three components (resistor, inductor, capacitor), focusing on algebraic summation.

Electric Fields Between Charged Plates

• Examination of electric fields generated between two parallel metal sheets with equal surface charge density but opposite signs.

• Question posed regarding net electric field between plates using known densities; relates back to previous derivations discussed.

Current Flow and Magnetic Field Interactions

• Description of current flowing through a wire segment along the x-axis; prompts calculation of magnetic field vector form and force.

• Discussion about work done when moving within a magnetic field; questions where maximum work occurs during movement.

Class Summary and Future Plans

• Acknowledgment that this class was brief yet important; encouragement for students to solve questions independently before seeking solutions.

• Commitment to provide solutions by 9 PM, urging students not to give up on challenging questions while maintaining focus on their studies.