Instructions Total Questions: 20 | Marks: 4 each | No Negative Marking Q1. Newton’s law of gravitation states force is proportional to: Product of masses Sum of masses Difference of masses Distance only Q2. Gravitational force inversely depends on: Square of distance Distance Cube of distance Mass Q3. Universal gravitational constant symbol: G g M k Q4. SI unit of gravitational constant: Nm²/kg² N/kg Joule Watt Q5. Acceleration due to gravity on Earth is nearly: 9.8 m/s² 98 m/s² 0.98 m/s² 1 m/s² Q6. Value of g decreases with: Height Mass increase Time Temperature only Q7. Escape velocity from Earth surface is approximately: 11.2 km/s 5 km/s 20 km/s 1 km/s Q8. Escape velocity formula: √(2GM/R) √(GM/R) GM/R None Q9. Orbital velocity of satellite depends on: Radius of orbit Mass of satellite Density of satellite Shape of satellite Q10. Orbital velocity formula: √(GM/R) √(2GM/R) GM/R² None Q11. Geostationary satellite period is: 24 hours 12 hours 48 hours 6 hours Q12. Weight of body at Earth center is: Zero Maximum Infinite Same as surface Q13. Gravitational potential energy formula: -GMm/R GMm/R mgh None Q14. Gravitational field intensity unit: N/kg Joule Watt Coulomb Q15. Kepler’s first law states planets move in: Elliptical orbits Circular orbits Parabolic paths Straight lines Q16. Kepler’s second law is law of: Equal areas Equal masses Equal distances Gravitation Q17. Kepler’s third law relation: T² ∝ R³ T ∝ R² T³ ∝ R² None Q18. Weightlessness in satellite is due to: Free fall motion Absence of gravity No atmosphere Magnetism Q19. Gravitational force is always: Attractive Repulsive Neutral Magnetic Q20. Relation between g and G: g = GM/R² g = G/R g = MR² None Submit Gravitation – IIT JEE Notes (Set 25) Introduction to Gravitation Definition Gravitation is the universal force of attraction between any two masses in the universe. Importance It explains planetary motion, satellite motion, tides, and falling of bodies toward Earth. Newton’s Law of Gravitation Statement Every particle attracts every other particle with a force directly proportional to product of their masses and inversely proportional to square of distance between them. Formula F = Gm₁m₂/r² Variables F = gravitational force G = universal gravitational constant m₁, m₂ = masses r = separation between centers Universal Gravitational Constant Symbol G Value G = 6.67 × 10⁻¹¹ Nm²/kg² Importance Its value remains same everywhere in the universe. Characteristics of Gravitational Force Main Features Always attractive, central in nature, long range force, and obeys inverse square law. Weak Force Gravitational force is weakest among fundamental forces. Acceleration Due to Gravity Definition Acceleration produced in a body due to Earth’s gravitational pull. Formula g = GM/R² Standard Value g ≈ 9.8 m/s² Variation of g with Height Relation Acceleration due to gravity decreases with increase in height above Earth surface. Approximate Formula gh = g(1 – 2h/R) Variation of g with Depth Relation Acceleration due to gravity decreases with depth below Earth surface. Formula gd = g(1 – d/R) Important Point g becomes zero at center of Earth. Variation of g Due to Earth Rotation Effect g is maximum at poles and minimum at equator. Reason Centrifugal force due to Earth rotation reduces effective gravity at equator. Mass and Weight Mass Amount of matter in a body and remains constant everywhere. Weight Force with which Earth attracts a body. Formula W = mg Key Insight Weight changes from place to place while mass remains constant. Gravitational Potential Definition Work done per unit mass in bringing a body from infinity to a point. Formula V = -GM/r Unit J/kg Gravitational Potential Energy Definition Energy possessed by a body due to gravitational interaction. Formula U = -GMm/r Important Point Potential energy is negative because gravitational force is attractive. Escape Velocity Definition Minimum velocity required for a body to escape Earth’s gravitational field permanently. Formula ve = √(2GM/R) Value for Earth Approximately 11.2 km/s. Important Point Escape velocity is independent of mass of body. Orbital Velocity Definition Velocity required for satellite to remain in stable orbit around Earth. Formula v = √(GM/R) Value Near Earth Approximately 7.9 km/s. Satellites Definition Objects revolving around planets under gravitational attraction. Natural Satellites Moon is natural satellite of Earth. Artificial Satellites Man-made satellites used for communication, weather, and navigation. Geostationary Satellite Definition Satellite appearing stationary relative to Earth. Conditions Orbital period must be 24 hours and orbit must lie in equatorial plane. Applications Communication and weather forecasting. Kepler’s Laws of Planetary Motion First Law Planets move in elliptical orbits with Sun at one focus. Second Law Line joining Sun and planet sweeps equal areas in equal intervals of time. Third Law Square of orbital period is proportional to cube of semi-major axis. T² ∝ R³ Weightlessness Definition Condition when apparent weight becomes zero. Cause in Satellites Satellites and astronauts remain in continuous free fall. Energy of Satellite Kinetic Energy K = GMm/2R Potential Energy U = -GMm/R Total Energy E = -GMm/2R Gravitational Field Intensity Definition Force experienced by unit mass placed at a point. Formula E = GM/r² Unit N/kg Tides Cause Tides are caused mainly due to gravitational pull of Moon and Sun. Types High tide and low tide. Conceptual Insights Key Understanding Gravitational force governs motion of celestial bodies and keeps planets and satellites in orbit. Common Mistakes Students often confuse orbital velocity with escape velocity and misuse signs in gravitational potential energy. Important Exam Concepts Conceptual Traps Escape velocity is √2 times orbital velocity near Earth surface. JEE Strategy Practice derivations, satellite motion numericals, Kepler’s laws, and variation of g thoroughly for IIT JEE preparation.

IIT JEE Physics Practice Paper – Waves (Set 24) Instructions Total Questions: 20 | Marks: 4 each | No Negative Marking Q1. Wave motion transfers: Energy Matter Mass Charge Q2. Mechanical waves require: Material medium Vacuum Electric field Magnetic field Q3. Speed of wave formula: v = fλ v = λ/f v = f/λ None Q4. SI unit of frequency: Hertz Meter Joule Newton Q5. Wavelength is distance between: Two consecutive crests Source and observer Two amplitudes None Q6. Longitudinal waves have particle vibration: Parallel to propagation Perpendicular to propagation Circular Random Q7. Transverse waves have particle vibration: Perpendicular to propagation Parallel to propagation Circular None Q8. Sound waves are: Longitudinal Transverse Electromagnetic Stationary Q9. Electromagnetic waves can travel in: Vacuum Solids only Liquids only Gases only Q10. Doppler effect occurs due to: Relative motion Reflection Refraction Diffraction Q11. Stationary waves are formed by: Superposition of waves Reflection only Refraction only Dispersion Q12. Points of zero displacement in stationary waves are: Nodes Antinodes Crests Troughs Q13. Points of maximum displacement are: Antinodes Nodes Sources None Q14. Speed of sound in air increases with: Temperature Humidity decrease Density decrease only None Q15. Audible sound frequency range: 20 Hz – 20 kHz Below 20 Hz Above 20 kHz 1 Hz – 10 Hz Q16. Infrasonic waves have frequency: Below 20 Hz Above 20 kHz Equal to light waves None Q17. Ultrasonic waves have frequency: Above 20 kHz Below 20 Hz Equal to radio waves None Q18. Intensity of wave is proportional to: Square of amplitude Amplitude Frequency only Wavelength only Q19. Beats are produced due to: Superposition of nearby frequencies Reflection Refraction Polarization Q20. Wave number is reciprocal of: Wavelength Frequency Time period Amplitude Submit Waves – IIT JEE Notes (Set 24) Introduction to Waves Definition A wave is a disturbance that transfers energy from one place to another without transfer of matter. Main Concept Particles of medium oscillate about their mean positions while energy propagates through the medium. Characteristics of Waves Amplitude Maximum displacement of particle from mean position. Wavelength Distance between two consecutive points in same phase, such as two crests or troughs. Frequency Number of oscillations completed in one second. Time Period Time taken to complete one oscillation. Wave Speed Distance traveled by wave per unit time. Wave Equation v = fλ Types of Waves Mechanical Waves Require material medium for propagation. Examples Sound waves, water waves, waves on string. Electromagnetic Waves Do not require any material medium and can travel through vacuum. Examples Light waves, radio waves, X-rays. Transverse Waves Definition Particles of medium vibrate perpendicular to direction of wave propagation. Examples Light waves and waves on stretched string. Important Feature Contain crests and troughs. Longitudinal Waves Definition Particles of medium vibrate parallel to direction of propagation. Examples Sound waves in air. Important Feature Contain compressions and rarefactions. Wave Motion Energy Transfer Waves transfer energy without transporting matter permanently. Particle Motion Particles oscillate around equilibrium positions. Speed of Mechanical Waves String Wave Speed v = √(T/μ) Variables T = tension in string μ = mass per unit length Key Insight Wave speed increases with tension. Sound Waves Nature Sound waves are longitudinal mechanical waves. Requirement Sound requires material medium for propagation. Speed of Sound Depends on elasticity and density of medium. Speed of Sound in Air Formula v = √(γP/ρ) Temperature Dependence Speed of sound increases with temperature. Humidity Effect Sound travels faster in humid air. Audible Sound Range Human Hearing Range 20 Hz to 20 kHz. Infrasonic Waves Frequency below 20 Hz. Ultrasonic Waves Frequency above 20 kHz. Applications of Ultrasonic Waves Medical Use Ultrasound imaging and therapy. Industrial Use Crack detection and cleaning. SONAR Used for underwater detection and distance measurement. Principle of Superposition Definition Resultant displacement equals algebraic sum of individual displacements. Importance Explains interference and stationary waves. Interference of Waves Constructive Interference Occurs when waves combine in same phase and amplitude increases. Destructive Interference Occurs when waves combine in opposite phase and amplitude decreases. Beats Definition Periodic variation in intensity due to superposition of two waves of nearly equal frequencies. Beat Frequency f = |f₁ – f₂| Application Tuning musical instruments. Stationary Waves Definition Produced due to superposition of two identical waves traveling in opposite directions. Nodes Points having zero displacement. Antinodes Points having maximum displacement. Formation of Standing Waves on Strings Fundamental Mode Lowest frequency mode of vibration. Harmonics Integral multiples of fundamental frequency. Resonance Definition Maximum amplitude occurs when driving frequency equals natural frequency. Examples Musical instruments and bridges. Doppler Effect Definition Apparent change in frequency due to relative motion between source and observer. Approaching Source Frequency appears higher. Receding Source Frequency appears lower. Intensity of Waves Definition Energy crossing unit area per second. Relation Intensity ∝ Amplitude² Wave Number Definition Number of waves per unit distance. Formula k = 1/λ Phase of a Wave Definition Specifies state of oscillation of particle at any instant. Phase Difference Difference in phase between two particles. Energy in Wave Motion Kinetic Energy Due to motion of particles. Potential Energy Due to elastic deformation of medium. Total Energy Remains conserved in ideal wave motion. Conceptual Insights Key Understanding Wave motion transfers energy while particles only oscillate around equilibrium positions. Common Mistakes Students often confuse longitudinal and transverse waves and mix up nodes with antinodes. Important Exam Concepts Conceptual Traps Sound waves cannot travel through vacuum because they require material medium. JEE Strategy Practice wave equations, Doppler effect numericals, stationary wave problems, and concepts of resonance thoroughly.

IIT JEE Physics Practice Paper – Oscillations and SHM (Set 23) Instructions Total Questions: 20 | Marks: 4 each | No Negative Marking Q1. Simple harmonic motion is: Periodic motion Circular motion Random motion Translational motion Q2. Restoring force in SHM is proportional to: Displacement Velocity Acceleration Mass Q3. Equation of SHM restoring force: F = -kx F = kx F = ma None Q4. Time period of spring-mass system: 2π√(m/k) 2π√(k/m) √(m/k) None Q5. Frequency is reciprocal of: Time period Velocity Amplitude Displacement Q6. Angular frequency relation: ω = 2πf ω = f/2π ω = T/2π None Q7. Maximum displacement in SHM is: Amplitude Frequency Velocity Period Q8. Velocity in SHM is maximum at: Mean position Extreme position Everywhere same None Q9. Acceleration in SHM is maximum at: Extreme position Mean position Zero everywhere None Q10. Total energy in SHM is proportional to: A² A 1/A √A Q11. Potential energy in SHM is maximum at: Extreme position Mean position Midpoint None Q12. Kinetic energy in SHM is maximum at: Mean position Extreme position Everywhere same None Q13. Phase difference in one complete oscillation: 2π π π/2 4π Q14. Simple pendulum time period formula: 2π√(L/g) 2π√(g/L) √(L/g) None Q15. Time period of simple pendulum depends on: Length Mass Amplitude only Density Q16. SHM projection is obtained from: Uniform circular motion Linear motion Random motion Projectile motion Q17. Unit of frequency: Hertz Joule Newton Watt Q18. Displacement equation of SHM: x = Asinωt x = vt x = at² None Q19. Mechanical energy in ideal SHM remains: Constant Increasing Decreasing Zero Q20. SHM acceleration is directed toward: Mean position Extreme position Tangential direction None Submit Oscillations and Simple Harmonic Motion – IIT JEE Notes (Set 23) Introduction to Oscillations Definition Oscillatory motion is the repeated to-and-fro motion of a body about its mean equilibrium position. Examples Simple pendulum, vibrating spring, tuning fork, and oscillating particles. Periodic Motion Definition Motion that repeats itself after equal intervals of time is called periodic motion. Time Period The time taken to complete one full oscillation. Frequency Number of oscillations completed in one second. Relation f = 1/T Simple Harmonic Motion (SHM) Definition SHM is a special type of oscillatory motion in which restoring force is directly proportional to displacement and directed toward mean position. Restoring Force Equation F = -kx Key Insight Negative sign shows restoring force acts opposite to displacement. Characteristics of SHM Main Features Motion is periodic, acceleration is variable, and restoring force always acts toward equilibrium position. Symmetry Motion is symmetric about mean position. Displacement Equation of SHM Equation x = A sin(ωt + φ) Variables A = amplitude ω = angular frequency φ = phase constant Amplitude Definition Maximum displacement of particle from mean position. Importance Determines maximum energy of oscillating particle. Angular Frequency Formula ω = 2πf Relation with Time Period ω = 2π/T Velocity in SHM Formula v = ω√(A² – x²) Maximum Velocity vmax = Aω Key Insight Velocity is maximum at mean position and zero at extreme positions. Acceleration in SHM Formula a = -ω²x Maximum Acceleration amax = Aω² Key Insight Acceleration is maximum at extreme positions and zero at mean position. Energy in SHM Total Energy E = ½kA² Kinetic Energy Maximum at mean position. Potential Energy Maximum at extreme positions. Conservation of Energy Total mechanical energy remains constant in ideal SHM. Phase in SHM Definition Phase specifies the state of oscillation of a particle at any instant. Phase Difference Difference in phase between two oscillating particles. Complete Oscillation Phase change in one complete oscillation is 2π radians. Spring-Mass System Time Period Formula T = 2π√(m/k) Variables m = mass attached k = spring constant Key Insight Heavier mass increases time period while stiffer spring decreases it. Simple Pendulum Definition A small bob suspended by light inextensible string oscillating under gravity. Time Period Formula T = 2π√(L/g) Variables L = length of pendulum g = acceleration due to gravity Key Insight Time period is independent of mass of bob. Conditions for Simple Pendulum SHM Small Angle Approximation Oscillations must have small angular displacement. Reason For small angles, sinθ ≈ θ. Projection of Uniform Circular Motion Concept SHM can be considered as projection of uniform circular motion on diameter. Importance Helps derive displacement, velocity, and acceleration equations. Damped Oscillations Definition Oscillations whose amplitude gradually decreases due to friction or resistance. Examples Real pendulum and vibrating tuning fork. Forced Oscillations Definition Oscillations produced by external periodic force. Example Vibrating machine parts. Resonance Definition When frequency of external force equals natural frequency of system, amplitude becomes maximum. Applications Musical instruments, radio tuning, bridges. Quality Factor Definition Measures sharpness of resonance. Key Insight Higher quality factor means lower energy loss. Important Graphs in SHM Displacement-Time Graph Sinusoidal graph representing periodic motion. Velocity-Time Graph Velocity leads displacement by phase π/2. Acceleration-Time Graph Acceleration is opposite in phase to displacement. Conceptual Insights Key Understanding In SHM, restoring force always tries to bring particle back to equilibrium position. Common Mistakes Students often confuse velocity and acceleration positions and forget phase relationships. Important Exam Concepts Conceptual Traps Velocity is maximum at mean position while acceleration is zero there. JEE Strategy Practice SHM equations, energy concepts, pendulum numericals, and phase relations thoroughly for IIT JEE problems.

Instructions Total Questions: 20 | Marks: 4 each | No Negative Marking Q1. Kinetic theory explains properties of: Gases Solids Magnets Light Q2. Ideal gas molecules are assumed to have: Negligible volume Large volume Infinite mass No motion Q3. Gas pressure arises due to: Molecular collisions Gravity Magnetism Heat only Q4. RMS speed formula is: √(3RT/M) √(RT/M) 3RT/M None Q5. Average kinetic energy of gas molecule is: (3/2)kT kT 3kT None Q6. Boltzmann constant symbol: k h R G Q7. Degree of freedom means: Independent ways to store energy Molecular force Heat transfer Pressure Q8. Monatomic gas has degrees of freedom: 3 2 5 6 Q9. Equipartition theorem gives energy per degree: (1/2)kT kT 2kT None Q10. Temperature is measure of: Average kinetic energy Pressure Volume Mass Q11. Mean free path is: Average distance between collisions Molecular diameter Gas pressure None Q12. SI unit of temperature: Kelvin Celsius Joule Watt Q13. Internal energy of ideal gas depends on: Temperature Pressure Volume Density Q14. Real gases deviate from ideal behavior due to: Molecular forces No collisions No motion Infinite volume Q15. Pressure of gas increases with: Temperature Decrease in collisions Vacuum None Q16. Most probable speed depends on: Temperature Color Charge Magnetism Q17. Kinetic theory assumes collisions are: Perfectly elastic Inelastic Magnetic None Q18. Gas molecules move in: Random motion Circular paths Straight fixed paths None Q19. Universal gas constant symbol: R k h G Q20. Maxwell distribution describes: Molecular speeds Pressure Heat transfer Electric field Submit Kinetic Theory of Gases – IIT JEE Notes (Set 22) Introduction to Kinetic Theory Definition Kinetic Theory of Gases explains the macroscopic properties of gases in terms of motion of their molecules. Main Idea Gas pressure, temperature, and volume arise due to continuous random motion of molecules. Assumptions of Kinetic Theory Molecular Nature Gas consists of a very large number of tiny molecules moving randomly in all directions. Negligible Volume Actual volume of molecules is negligible compared to volume of gas container. No Intermolecular Forces Except during collisions, no forces act between gas molecules. Elastic Collisions Collisions between molecules and container walls are perfectly elastic. Random Motion Molecules move randomly with different speeds. Gas Pressure Cause of Pressure Pressure of a gas arises due to collisions of molecules with walls of the container. Pressure Formula P = (1/3)ρv²rms Variables ρ = density of gas vrms = root mean square speed Root Mean Square Speed Definition RMS speed is the square root of average of squares of molecular speeds. Formula vrms = √(3RT/M) Key Insight RMS speed increases with temperature. Average Kinetic Energy Formula KE = (3/2)kT Variables k = Boltzmann constant T = absolute temperature Key Insight Average kinetic energy depends only on temperature. Boltzmann Constant Symbol k Value k = 1.38 × 10⁻²³ J/K Importance Connects microscopic molecular energy with temperature. Temperature and Molecular Motion Concept Temperature is a measure of average kinetic energy of gas molecules. Key Insight Higher temperature means faster molecular motion. Degrees of Freedom Definition Independent ways in which a molecule can possess energy. Monatomic Gas Has 3 translational degrees of freedom. Diatomic Gas Has translational and rotational degrees of freedom. Equipartition of Energy Statement Energy is equally distributed among all active degrees of freedom. Energy per Degree Each degree contributes (1/2)kT energy. Total Energy Total energy = (f/2)kT Variables f = degrees of freedom Mean Free Path Definition Average distance traveled by a molecule between two successive collisions. Factors Affecting Mean Free Path Pressure, temperature, and molecular size. Ideal Gas Equation Formula PV = nRT Variables P = pressure V = volume n = number of moles R = gas constant T = absolute temperature Universal Gas Constant Symbol R Value R = 8.314 J mol⁻¹ K⁻¹ Relation Between R and k Formula R = NAk Variables NA = Avogadro number Maxwell Speed Distribution Concept Gas molecules have different speeds distributed statistically. Types of Speeds Most probable speed, average speed, and RMS speed. Relation vrms > vavg > vmp Most Probable Speed Definition Speed possessed by maximum number of molecules. Formula vmp = √(2RT/M) Average Speed Formula vavg = √(8RT/πM) Key Insight Average speed is less than RMS speed. Real Gases Definition Actual gases which deviate from ideal gas behavior. Reason for Deviation Intermolecular forces and finite molecular volume. Boyle’s Law Statement At constant temperature, pressure is inversely proportional to volume. Formula PV = constant Charles Law Statement At constant pressure, volume is directly proportional to temperature. Formula V/T = constant Gay-Lussac Law Statement At constant volume, pressure is directly proportional to temperature. Formula P/T = constant Avogadro’s Law Statement Equal volumes of all gases at same temperature and pressure contain equal number of molecules. Conceptual Insights Key Understanding Kinetic theory connects microscopic molecular motion with observable gas properties. Common Mistakes Students often confuse RMS speed with average speed and misuse temperature units in formulas. Important Exam Concepts Conceptual Traps Average kinetic energy depends only on temperature and not on pressure or volume. JEE Strategy Focus on derivations, gas laws, RMS speed formulas, and molecular motion concepts. Practice numerical problems thoroughly.

Instructions Total Questions: 20 | Marks: 4 each | No Negative Marking Q1. Zeroth law of thermodynamics defines: Temperature Heat Work Entropy Q2. First law of thermodynamics is: ΔQ = ΔU + W PV = nRT F = ma None Q3. SI unit of heat: Joule Calorie Kelvin Watt Q4. Isothermal process occurs at constant: Temperature Pressure Volume Energy Q5. Adiabatic process occurs with: No heat exchange Constant pressure Constant volume Infinite heat Q6. Ideal gas equation is: PV = nRT V = IR P = VI None Q7. Specific heat at constant pressure is: Cp Cv γ R Q8. Relation between Cp and Cv: Cp – Cv = R Cp + Cv = R Cp/Cv = R None Q9. γ represents: Cp/Cv Cv/Cp Pressure Volume Q10. Internal energy of ideal gas depends on: Temperature Pressure Volume Density Q11. Work done in cyclic process equals: Area under PV graph Pressure Heat only None Q12. Efficiency of Carnot engine depends on: Temperature Pressure Volume Density Q13. Carnot engine efficiency formula: 1 – T₂/T₁ T₂/T₁ T₁/T₂ None Q14. Entropy is related to: Disorder Force Velocity Momentum Q15. In isochoric process volume remains: Constant Variable Zero Infinite Q16. In isobaric process pressure remains: Constant Variable Zero Infinite Q17. Adiabatic relation is: PVᵞ = constant PV = constant P/T = constant None Q18. Heat engine converts: Heat into work Work into heat Electricity into heat None Q19. Refrigerator works on: Reverse heat engine Nuclear energy Electrical heating None Q20. Second law of thermodynamics introduces: Entropy Force Velocity Current Submit Thermodynamics – IIT JEE Notes (Set 21) Introduction to Thermodynamics Definition Thermodynamics is the branch of physics that deals with heat, temperature, work, and energy transformations in physical systems. Scope It explains how heat energy converts into mechanical work and vice versa. Thermodynamic System Definition A thermodynamic system is a specified portion of matter under study. Types of Systems Open system, closed system, and isolated system. Thermodynamic Variables State Variables Pressure, volume, temperature, and internal energy. Equation of State Relation between thermodynamic variables of a system. Zeroth Law of Thermodynamics Statement If two systems are separately in thermal equilibrium with a third system, they are in thermal equilibrium with each other. Importance This law defines the concept of temperature. First Law of Thermodynamics Statement Heat supplied to a system equals increase in internal energy plus work done by the system. Formula ΔQ = ΔU + W Key Insight It is based on conservation of energy. Internal Energy Definition Total kinetic and potential energy of molecules inside a system. Ideal Gas Internal energy of an ideal gas depends only on temperature. Heat and Work Heat Energy transferred due to temperature difference. Work Energy transferred when a system changes volume against external pressure. Work Formula W = ∫PdV Specific Heat Capacity Definition Amount of heat required to raise temperature of unit mass by one degree. Specific Heat at Constant Volume Cv Specific Heat at Constant Pressure Cp Mayer’s Relation Formula Cp – Cv = R Importance Valid for ideal gases. Ratio of Specific Heats Formula γ = Cp/Cv Importance Used in adiabatic processes. Ideal Gas Equation Formula PV = nRT Variables P = pressure, V = volume, n = number of moles, R = gas constant, T = temperature. Isothermal Process Definition Process occurring at constant temperature. Condition PV = constant Key Insight Internal energy change is zero for ideal gas. Adiabatic Process Definition Process in which no heat exchange occurs between system and surroundings. Condition PVᵞ = constant Key Insight Temperature changes during adiabatic expansion or compression. Isochoric Process Definition Process occurring at constant volume. Work Done Work done is zero because volume does not change. Isobaric Process Definition Process occurring at constant pressure. Work Done W = PΔV PV Diagram Importance Area under PV curve represents work done by the gas. Cyclic Process In cyclic process, system returns to initial state. Second Law of Thermodynamics Kelvin-Planck Statement No engine can convert all heat into work completely. Clausius Statement Heat cannot flow spontaneously from colder body to hotter body. Entropy Definition Entropy is a measure of randomness or disorder of a system. Key Insight Entropy increases in irreversible processes. Heat Engine Definition A device that converts heat energy into mechanical work. Efficiency η = W/Q₁ Carnot Engine Importance Ideal heat engine with maximum possible efficiency. Efficiency Formula η = 1 – T₂/T₁ Key Insight Efficiency depends only on source and sink temperatures. Refrigerator Working Principle Works as reverse heat engine. Coefficient of Performance COP = Q₂/W Kinetic Theory of Gases Basic Assumptions Gas molecules are in random motion and collisions are perfectly elastic. Pressure of Gas Pressure arises due to collisions of molecules with container walls. Root Mean Square Speed Formula vrms = √(3RT/M) Key Insight Higher temperature increases molecular speed. Degrees of Freedom Definition Independent ways in which molecules can store energy. Examples Monatomic gases have 3 degrees of freedom. Equipartition of Energy Statement Energy is equally distributed among all degrees of freedom. Average Energy Each degree contributes (1/2)kT energy. Conceptual Insights Key Understanding Thermodynamics connects heat transfer with mechanical work and energy conservation. Common Mistakes Students often confuse adiabatic and isothermal processes and forget sign conventions in thermodynamics. Important Exam Concepts Conceptual Traps Internal energy of ideal gas depends only on temperature, not pressure or volume. JEE Strategy Practice PV diagrams, thermodynamic processes, and numerical problems on heat engines thoroughly. Focus on derivations and conceptual clarity.

Instructions Total Questions: 20 | Marks: 4 each | No Negative Marking Q1. Photoelectric effect proves light has: Particle nature Wave nature only Mechanical nature None Q2. Einstein photoelectric equation is: hν = φ + KE E = mc² V = IR None Q3. Threshold frequency is minimum frequency needed for: Photoelectric emission Reflection Refraction Diffraction Q4. Photon energy formula: E = hν E = mc² E = qV None Q5. de Broglie wavelength formula: λ = h/p λ = p/h λ = hv None Q6. Bohr model explains: Hydrogen spectrum Reflection Diffraction Magnetism Q7. Radius of Bohr orbit depends on: n² n 1/n None Q8. Energy of nth orbit is proportional to: -1/n² n² n None Q9. Nuclear force is: Strong and short range Weak and long range Electric force None Q10. Radioactivity was discovered by: Becquerel Newton Bohr Einstein Q11. Half-life is time required for: Half nuclei to decay Full decay Energy emission None Q12. Alpha particles are: Helium nuclei Electrons Protons Neutrons Q13. Beta particles are: Electrons Protons Helium nuclei None Q14. Gamma rays are: Electromagnetic waves Particles Protons None Q15. Mass-energy equivalence formula: E = mc² V = IR F = ma None Q16. Nuclear fission is: Splitting of heavy nucleus Combining nuclei Electron emission None Q17. Nuclear fusion is: Combining light nuclei Splitting nuclei Gamma emission None Q18. Semiconductor has conductivity between: Conductor and insulator Metals only Vacuum and gas None Q19. Diode allows current in: One direction Both directions No direction None Q20. LED stands for: Light Emitting Diode Light Energy Device Low Energy Diode None Submit Modern Physics – IIT JEE Notes (Set 20) Introduction to Modern Physics Overview Modern Physics deals with concepts developed after classical physics failed to explain microscopic phenomena. It includes quantum mechanics, atomic physics, nuclear physics, and semiconductor electronics. Importance Modern Physics forms the foundation of lasers, semiconductors, nuclear reactors, and electronic devices. Photoelectric Effect Definition The emission of electrons from a metal surface when light of suitable frequency falls on it is called photoelectric effect. Experimental Observations Photoelectric emission occurs instantly when frequency exceeds threshold frequency. Einstein’s Explanation Einstein explained photoelectric effect using particle nature of light called photons. Einstein Photoelectric Equation hν = φ + KEmax Key Terms h = Planck’s constant ν = frequency of incident light φ = work function KE = kinetic energy of emitted electrons Photon Definition A photon is a packet of electromagnetic energy. Energy Formula E = hν Momentum Formula p = h/λ Threshold Frequency Definition Minimum frequency required to eject photoelectrons from a metal surface. Key Insight No photoelectric emission occurs below threshold frequency regardless of intensity. de Broglie Hypothesis Statement Every moving particle has wave nature associated with it. de Broglie Wavelength λ = h/p Importance This established wave-particle duality of matter. Bohr’s Atomic Model Main Postulates Electrons revolve around nucleus only in certain allowed circular orbits without radiating energy. Angular Momentum Quantization mvr = nh/2π Energy Levels En = -13.6/n² eV Hydrogen Spectrum Spectral Series Lyman, Balmer, Paschen, Brackett, and Pfund series. Balmer Series Visible region of hydrogen spectrum. Rydberg Formula 1/λ = R(1/n₁² – 1/n₂²) Atomic Radius Bohr Radius Radius of first orbit in hydrogen atom is called Bohr radius. Formula rn ∝ n² X-Rays Production Produced when high-speed electrons strike a metal target. Properties X-rays are electromagnetic waves with very short wavelength and high penetrating power. Radioactivity Definition Spontaneous disintegration of unstable nuclei with emission of radiation. Discovery Discovered by Henri Becquerel. Types of Radioactive Emissions Alpha Particles Helium nuclei carrying +2 charge. Beta Particles Fast moving electrons. Gamma Rays High energy electromagnetic waves. Radioactive Decay Law Formula N = N₀e-λt Decay Constant λ represents probability of decay per unit time. Half-Life Definition Time required for half of radioactive nuclei to decay. Formula T1/2 = 0.693/λ Mean Life Definition Average lifetime of radioactive nuclei. Formula τ = 1/λ Nuclear Binding Energy Concept Energy required to separate nucleus into individual nucleons. Mass Defect Difference between actual nuclear mass and sum of masses of nucleons. Einstein Relation E = mc² Nuclear Fission Definition Splitting of heavy nucleus into lighter nuclei with release of energy. Example Uranium-235 fission. Applications Nuclear reactors and atomic bombs. Nuclear Fusion Definition Combination of light nuclei to form heavier nucleus. Example Fusion of hydrogen nuclei in the Sun. Key Insight Fusion releases more energy per unit mass than fission. Semiconductors Definition Materials having conductivity between conductors and insulators. Examples Silicon and Germanium. Intrinsic and Extrinsic Semiconductors Intrinsic Semiconductor Pure semiconductor without impurities. Extrinsic Semiconductor Semiconductor doped with impurities to increase conductivity. p-Type and n-Type Semiconductors p-Type Majority charge carriers are holes. n-Type Majority charge carriers are electrons. p-n Junction Diode Definition A semiconductor device formed by joining p-type and n-type materials. Forward Bias Allows current to flow easily. Reverse Bias Opposes current flow. LED Full Form Light Emitting Diode. Working Emits light when current passes through it. Transistor Function Used for amplification and switching. Types NPN and PNP transistors. Conceptual Insights Key Understanding Modern Physics combines wave and particle nature to explain microscopic phenomena. Common Mistakes Students often confuse threshold frequency with intensity and mix up fission and fusion processes. Important Exam Concepts Conceptual Traps Photoelectric current depends on intensity while kinetic energy depends on frequency. JEE Strategy Focus on formulas, graphs, and conceptual understanding of photoelectric effect, Bohr model, and semiconductors. Practice numerical problems regularly.

Instructions Total Questions: 20 | Marks: 4 each | No Negative Marking Q1. Interference of light proves light is: Wave Particle Neutral Magnetic Q2. Young’s double slit experiment demonstrates: Interference Reflection Polarization Refraction Q3. Fringe width formula: β = λD/d β = dD/λ β = λ/dD None Q4. Diffraction occurs due to: Bending of light Reflection Refraction Dispersion Q5. Polarization proves light is: Transverse Longitudinal Mechanical Stationary Q6. Path difference for constructive interference: nλ (2n+1)λ/2 λ/4 None Q7. Path difference for destructive interference: (2n+1)λ/2 nλ λ None Q8. Coherent sources have: Constant phase difference Different frequencies Different amplitudes None Q9. Central fringe in YDSE is: Bright Dark Colored Invisible Q10. Single slit diffraction central maximum is: Brightest Dark Equal intensity None Q11. Polarizer is used to produce: Plane polarized light White light Coherent light None Q12. Brewster’s angle relation: tanθ = n sinθ = n cosθ = n None Q13. Diffraction is significant when slit size is: Comparable to wavelength Very large Infinite None Q14. Interference requires: Coherent sources White light only Mirrors None Q15. Huygens principle explains: Wave propagation Electric field Magnetism Gravity Q16. Monochromatic light means: Single wavelength Multiple wavelengths White light None Q17. Angular width of diffraction ∝ λ/a a/λ λa None Q18. Unpolarized light vibrates in: All planes One plane Horizontal only None Q19. Interference pattern consists of: Bright and dark fringes Only bright fringes Only dark fringes None Q20. Wave optics is based on: Wave nature of light Particle nature Nuclear theory None Submit Wave Optics – IIT JEE Notes (Set 19) Introduction to Wave Optics Basic Concept Wave optics explains the behavior of light using its wave nature. It includes phenomena such as interference, diffraction, and polarization which cannot be explained by ray optics. Wave Nature of Light Light behaves as a transverse electromagnetic wave and exhibits properties like superposition and interference. Huygens Principle Statement Every point on a wavefront acts as a source of secondary wavelets which spread in all directions with the speed of light. Importance Huygens principle explains reflection, refraction, and propagation of light waves. Wavefront Definition A wavefront is the locus of all points vibrating in the same phase. Types of Wavefronts Spherical wavefront, cylindrical wavefront, and plane wavefront. Interference of Light Definition Interference is the redistribution of intensity due to superposition of two coherent light waves. Constructive Interference Occurs when waves meet in phase and intensity becomes maximum. Condition Path difference = nλ Destructive Interference Occurs when waves meet out of phase and intensity becomes minimum. Condition Path difference = (2n + 1)λ/2 Young’s Double Slit Experiment (YDSE) Experiment Thomas Young demonstrated interference using two coherent light sources obtained from a single source. Fringe Width Formula β = λD/d Variables λ = wavelength, D = distance between slit and screen, d = slit separation. Key Insight Fringe width increases with wavelength and screen distance. Coherent Sources Definition Sources having same frequency and constant phase difference. Importance Stable interference pattern requires coherent sources. Diffraction of Light Definition Diffraction is the bending of light around edges and obstacles. Condition Diffraction becomes significant when obstacle or slit size is comparable to wavelength. Single Slit Diffraction Central Maximum The central bright fringe is widest and brightest. Angular Width Angular width = 2λ/a Key Insight Smaller slit width produces greater diffraction spread. Polarization of Light Definition Polarization is the phenomenon of restricting vibrations of light to one plane. Importance Polarization proves that light is a transverse wave. Plane Polarized Light Definition Light vibrating in only one plane perpendicular to direction of propagation. Production Produced using polarizers such as Polaroids. Brewster’s Law Formula tanθB = n Meaning At Brewster’s angle, reflected and refracted rays are perpendicular to each other. Malus Law Formula I = I₀cos²θ Explanation Intensity of polarized light depends on angle between polarizer and analyzer axes. Superposition Principle Concept When two or more waves overlap, resultant displacement equals algebraic sum of individual displacements. Application Used in interference and diffraction analysis. Monochromatic Light Definition Light having single wavelength and single frequency. Example Laser light is nearly monochromatic. Intensity Distribution in Interference Bright Fringe Maximum intensity occurs due to constructive interference. Dark Fringe Minimum intensity occurs due to destructive interference. Comparison Between Interference and Diffraction Interference Produced by superposition of waves from two coherent sources. Diffraction Produced due to bending of waves from different parts of same wavefront. Applications of Wave Optics Interference Applications Thin film coatings, anti-reflection coatings, interferometers. Diffraction Applications CD/DVD technology, diffraction gratings, spectroscopy. Polarization Applications 3D movies, sunglasses, LCD screens. Important Relationships Fringe Width β = λD/d Diffraction Minima Condition a sinθ = nλ Brewster Angle tanθ = n Conceptual Insights Key Understanding Wave optics explains phenomena that depend on superposition and wave behavior of light. Common Mistakes Students often confuse interference and diffraction patterns. Interference fringes are equally spaced, while diffraction fringes are not. Important Exam Concepts Conceptual Traps Polarization is possible only for transverse waves. Central diffraction maximum is widest. JEE Strategy Focus on derivations, formulas, and conceptual clarity. Practice YDSE numericals, diffraction problems, and polarization concepts thoroughly.

IIT JEE Physics Practice Paper – Electromagnetic Induction & AC (Set 18) Instructions Total Questions: 20 | Marks: 4 each | No Negative Marking Q1. Faraday’s law relates induced emf with: Change in magnetic flux Electric field Resistance Charge Q2. SI unit of magnetic flux: Weber Tesla Henry Volt Q3. Lenz’s law is based on: Conservation of energy Momentum Force None Q4. Induced emf formula: E = -dΦ/dt V = IR P = VI None Q5. Self inductance unit: Henry Tesla Weber Volt Q6. Energy stored in inductor: ½LI² LI I²/L None Q7. Transformer works on: Mutual induction Self induction Reflection None Q8. AC frequency in India: 50 Hz 60 Hz 100 Hz 25 Hz Q9. RMS value of AC current: I₀/√2 I₀ √2I₀ None Q10. Average AC current over complete cycle: Zero Maximum Infinite None Q11. Capacitive reactance formula: Xc = 1/ωC Xc = ωL Xc = IR None Q12. Inductive reactance formula: XL = ωL XL = 1/ωC XL = IR None Q13. Resonance in LCR circuit occurs when: XL = XC XL > XC XC > XL None Q14. Power factor is: cosφ sinφ tanφ None Q15. AC generator converts: Mechanical to electrical energy Electrical to mechanical Heat to electrical None Q16. Eddy currents are reduced using: Laminated core Thick core Plastic core None Q17. Back emf in motor is due to: Electromagnetic induction Resistance Friction None Q18. Instantaneous AC voltage equation: V = V₀sinωt V = IR V = P/t None Q19. Transformer cannot work with: DC AC Both None Q20. Resonance frequency formula: 1/2π√LC 2π√LC √LC None Submit Electromagnetic Induction & Alternating Current – IIT JEE Notes (Set 18) Electromagnetic Induction Definition Electromagnetic induction is the phenomenon of production of induced emf and current in a conductor whenever magnetic flux linked with it changes. Discovery Michael Faraday discovered electromagnetic induction experimentally. Magnetic Flux Definition Magnetic flux is the total magnetic field passing through a surface. Formula Φ = BA cosθ Unit The SI unit of magnetic flux is Weber (Wb). Faraday’s Laws of Electromagnetic Induction First Law Whenever magnetic flux linked with a circuit changes, an emf is induced in the circuit. Second Law The magnitude of induced emf is proportional to the rate of change of magnetic flux. Formula E = – dΦ/dt Key Insight The negative sign represents Lenz’s law. Lenz’s Law Statement The direction of induced current is such that it opposes the cause producing it. Importance Lenz’s law is based on conservation of energy. Motional EMF Formula E = Blv Concept When a conductor moves in a magnetic field, emf is induced across its ends. Self Induction Definition The phenomenon in which changing current in a coil induces emf in the same coil. Self Inductance L = Φ/I Unit Henry (H) Energy Stored in an Inductor Formula U = ½LI² Key Insight Inductors store energy in magnetic field. Mutual Induction Definition Changing current in one coil induces emf in nearby coil. Application Used in transformers. Transformer Working Principle Transformer works on mutual induction. Turns Ratio Vp/Vs = Np/Ns Step-Up Transformer Increases voltage and decreases current. Step-Down Transformer Decreases voltage and increases current. Eddy Currents Definition Eddy currents are circulating currents induced in bulk conductors. Reduction Method Reduced using laminated iron cores. Applications Induction furnace, magnetic braking, speedometers. Alternating Current (AC) Definition Alternating current changes magnitude and direction periodically. AC Frequency in India 50 Hz AC Voltage Equation Formula V = V₀ sinωt Current Equation I = I₀ sinωt RMS Value Definition RMS value is the effective value of AC equivalent to DC producing same heating effect. Formula Irms = I₀/√2 Vrms = V₀/√2 Average Value of AC Important Point Average value of alternating current over complete cycle is zero. AC Circuits Pure Resistor Circuit Voltage and current are in phase. Pure Inductor Circuit Current lags voltage by 90°. Pure Capacitor Circuit Current leads voltage by 90°. Reactance Inductive Reactance XL = ωL Capacitive Reactance XC = 1/ωC Key Insight Inductive reactance increases with frequency, while capacitive reactance decreases. LCR Circuit Resonance Condition XL = XC Resonance Frequency f = 1/2π√LC Key Insight At resonance, impedance becomes minimum and current becomes maximum. Power in AC Circuit Formula P = Vrms Irms cosφ Power Factor cosφ Importance Higher power factor means efficient power transmission. AC Generator Working Principle Based on electromagnetic induction. Function Converts mechanical energy into electrical energy. Back EMF Concept In electric motors, induced emf opposes applied voltage and is called back emf. Importance Protects motor from excessive current. Conceptual Insights Key Understanding Electromagnetic induction always opposes change in magnetic flux. Common Mistakes Students often confuse RMS value with average value and forget phase relations in AC circuits. Important Exam Concepts Conceptual Traps Transformer cannot work on DC because magnetic flux must change continuously. JEE Strategy Practice formulas, phase diagrams, and resonance problems thoroughly. Focus on Faraday’s law, transformers, and AC circuit analysis.