Mastering Class 11 Physics: Complete Revision and Important Questions for NEET by PW
Class 11 Physics accounts for nearly half of the NEET paper, yet many aspirants find it overwhelming due to lengthy derivations, vector rules, and multi-step numerical calculations. Balancing school exams with competitive entrance preparation makes it challenging to retain every formula and concept across all chapters.
Physics Wallah’s Maharevision bridges this gap by connecting foundational theory directly with high-yield exam questions. This complete class provides chapter summaries, short problem-solving tricks, and step-by-step solutions to past examination questions so that you can revise the entire syllabus quickly and score top marks in NEET 2026.
Chapter 1: Units and Measurement
Key NEET focus areas include dimensions, error analysis, significant figures, and measuring instruments.
- Spring Constant Errors
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Parallel combination: K = K1 + K2 Percentage error = (Change in K / K) × 100
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Series combination: 1/K = 1/K1 + 1/K2
- Dimensional Analysis and Principle of Homogeneity
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Only quantities with identical dimensions can be added or equated.
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For an equation such as P = a/(bt²) + gh, equate the dimensions of each term. For example, [P] = [ML⁻¹T⁻²] to determine the unknown dimensions.
- Relative and Fractional Error
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Mean value: A mean = Sum of all measured values / Number of measurements
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Mean absolute error: Average of the absolute differences between each measured value and the mean value.
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General error propagation for X = AᵃBᵇ/Cᶜ: Fractional error in X = a × (Error in A / A) + b × (Error in B / B) + c × (Error in C / C)
- Unit Derivation Example (ε₀E/t)
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From E = q/(4πε₀r²), we get ε₀E/t = q/(4πr²t).
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Since q/t represents current (A) and r² represents area (m²), the SI unit is A/m².
- Significant Figures Rules
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Addition and subtraction: Round off to the fewest decimal places among the given values.
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Multiplication and division: Round off to the fewest significant figures among the given values.
- Vernier Caliper and Screw Gauge
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Observed reading = Main scale reading + (Coinciding division × Least count)
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True value = Observed reading − Zero error (with its sign accounted for).
Chapter 2: Motion in a Straight Line
Key topics for examination include Calculus-based problems, Graphs (position-time, velocity-time, acceleration-time), and Uniformly Accelerated Motion (especially Motion Under Gravity).
Velocity from Displacement (x to v):
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Differentiate displacement: v=dxdt.
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For x=(3t+5)2, v=2(3t+5)(3)=6(3t+5). Velocity increases linearly with time.
Uniform Acceleration Shortcut (v2=kr):
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Any relation of the form v2x or vx indicates constant acceleration.
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Differentiating gives $2v a = kv \implies a = \frac{k}{2}$. At t=1s, velocity is v=at=k2.
Motion Under Gravity (Simultaneous Arrival):
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Free-fall time from height H: t=2Hg (for 180m, t=6s).
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If a second ball is thrown 3s later, time available is t'=6-3=3s. Using H=ut'+12gt'2, solve to get u=45m/s.
Maximum Height Scaling (Hu2):
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Maximum height is H=u22g (independent of mass).
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If projection speed increases to 4u, the new height increases by a factor of 42=16 (H'=16H=800m).
Slipping on a Vertical Circular Chord:
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For a chord of a vertical circle of radius R inclined at angle , distance is s=2R , and acceleration is a=g.
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Time to slide from rest: t=2Rg (completely independent of angle ).
Chapter 3: Motion in a Plane
This chapter primarily covers Projectile Motion (most important) and Relative Motion (river-boat, rain-man problems).
Range & Height Relation: Using HR=4, if R=2H, then =2 and R=4u25g.
Tower Projection: Range X=u2Hg. If X4X and H4H, the new speed is u'=2u.
Circular Acceleration: Net acceleration anet=ac2+at2=v2R2+g2. Centripetal acceleration (ac) is mandatory to change direction; tangential acceleration (at) is optional and changes speed.
Velocity Equality: For vx=vy, time t=u(-)g (valid only when >45).
Relative Motion:
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River-Boat: To cross directly opposite, =vrvsw. Angle with river flow is 90+ (e.g., 90+30=120).
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Rain-Man: vrel2=vrain2+vman2.
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Collision Condition: Two particles collide if their relative velocity vector aligns with their line-of-joining unit vector.
Chapter 4: Newton's Laws of Motion (NLM)
Key topics include Impulse-Momentum, Pulley Problems, Friction, and Circular Dynamics. Friction is particularly important for challenging problems.
Friction on Pulling: For a block pulled at angle , normal force N=mg-F and k=FN.
Pseudo Force: In an accelerating wedge frame (acceleration a to left), acceleration down the incline is a'=g+a.
Angle of Repose & Sand Cone: Max height h=r; maximum volume V=13r3.
Impulse & Thrust:
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Wall Collision: Favg=2mut ( with normal).
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Rocket Propulsion: vedmdt=m(g+a).
Elevator Apparent Weight: N=m(g-a) when accelerating downward.
Movable Pulley: If block on movable pulley has acceleration a, connected block moves with 2a.
Block-on-Block Friction: Common acceleration limit is a=sg (force on bottom) or a=smgM (force on top).
Chapter 5: Work, Energy, and Power
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Key topics are Vertical Circular Motion, Power, and Work Energy Theorem.
Work Done: W=Fd. Normal force work is zero (WN=0); friction work is negative (Wf=-fd).
Constant Power: If P=const, then vt1/2 and displacement xt3/2.
Equilibrium from U–x Graphs: dUdx=0. Local minimum is stable; local maximum is unstable.
Galileo Odd-Integer Rule: For constant force from rest, distance ratio in equal time intervals is $1:3:5\dots$, meaning K ratio is also $1:3:5\dots
Chapter 6: Center of Mass and Collisions
This chapter covers Finding Center of Mass, Motion of Center of Mass, and Collisions.
Discrete COM: XCM=miximi. For particles 1,2,3kg on side 2m triangle, distance from origin is 2m.
Cavity Method: XCM=A1x1-A2x2A1-A2. A cut-out disc of radius R/4 shifts COM by -R20.
Explosions & Collisions:
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Internal explosion conserves linear momentum (p=0).
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Perfectly inelastic collision has maximum kinetic energy loss: K=12mMm+Murel2.
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Energy loss rebound height: h'=(1-fractionlost)h.
Chapter 7: Rotational Motion
Moment of Inertia is the most crucial topic. Others include Torque and Equilibrium, Angular Momentum and its Conservation, and Rolling Motion.
Parallel Axis Theorem: I=ICM+Md2. For a ring about an in-plane axis at distance 2R/3: I=1718MR2.
Radius of Gyration: K=IM.
Angular Momentum: L=mvxH=mv342g for a projectile at 45.
Angular Acceleration of Pivoted Rod: =netIpivot.
Conservation of Angular Momentum: If ext=0, Li=Lf. Used when a bullet hits and sticks to a suspended rod: mvL=Isystem.
Static Equilibrium (Ladder Problem): Wall reaction N1=groundfrictionf=mg2.
Chapter 8: Gravitation
Key topics: Variation in g, Gravitational Potential Energy, Escape Speed, and Satellite Motion.
Two Attracting Free Masses: COM remains at rest. Distance covered is inversely proportional to mass: m1x1=m2x2.
Variation in g with Height: g'=g(1+h/R)2. At h=R/4, weight decreases by $36\%$.
Speed at Infinity (v>ve): v=v2-ve2.
Modified Gravity Laws (Fr-n): Orbital period scales as Tr(n+1)/2.
Work to Lift Mass: W=mgh1+h/R.
Kepler’s Third Law: $T^2 \propto r^3 \implies \frac{\Delta T}{T} = \frac{3}{2}\left(\frac{\Delta r}{r}\right)$.
Shell Potential: Potential inside a spherical shell of radius R is constant: V=-GMR
Chapter 9: Simple Harmonic Motion (SHM)
Key areas: Spring-Mass Systems, Pendulums, Energy in SHM, and Equations of SHM.
Velocity & Acceleration: v=A2-x2, a=2A.
Spring Modifications: kL=constant. Cutting spring into lengths L/3 and 2L/3 gives k1=3k and k2=32k.
Lift Effects: Acceleration in an elevator alters equilibrium elongation (x=mgeffk), but angular frequency =km remains unchanged.
Physical Pendulum: T=2Imgd=2L2+K2gL.
Energy Ratio: KU=A2-x2x2.
Liquid Immersion: Pendulum period increases: T'=Tggeff=T11-L/B.
Constrained Barrier: Wall at x=A/2 shortens the cycle time from T to 23T.
Chapter 10: Waves
Key areas: Standing Waves, Beats, and Waves on a String.
Boundary Reflection: Denser boundary induces a (180) phase change. Reflected amplitude Ar=RenergyAi.
Sonometer Wire: Frequency fT. Beat equation: f-ff+f=T1T2.
Organ Pipes:
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Closed pipe (1st overtone): f=3v4L1.
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Open pipe (3rd overtone): f=4v2L2.
String Wave Velocity: v=k=T=mgA.
Chapter 11: Kinetic Theory of Gases (KTG) and Thermodynamics
Exam focus: Energy and Mixing of Gases, Thermodynamic Processes.
Ideal Gas Pressure Ratio: At constant V,T, pressure scales with moles: PmM.
Isochoric Heating: At constant volume, PP=TT.
Specific Heat Ratio (): =1+2f. Rigid diatomic (f=5,=7/5); vibrating diatomic (f=7,=9/7).
Mean Free Path: =kT2d2P. Under constant pressure, T.
Adiabatic Processes: PV=const and TV-1=const. Work done: W=nR(Ti-Tf)-1.
Heat Engine Efficiency: =1-QoutQin.
Chapter 12: Thermal Properties of Matter
Key topics: Thermal Expansion, Calorimetry (phase changes), Heat Transfer (Conduction, Newton's Law of Cooling).
Elasticity: Wire elongation L=FLAY. Breaking force FB=BreakingStressA.
Cavity Volume: Vcavity=Vdisplaced-Vmaterial.
Continuity & Bernoulli: A1v1=A2v2; P1-P2=12(v22-v12). Efflux velocity: v=2gh.
Surface Tension:
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Drop splitting (1n drops): Work required W=4R2S(n1/3-1).
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Excess pressure in bubble: P=4SR. Volume ratio V1V2=P2P13.
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Surface pull: Thin ring F=mg+S(4R); Solid disc F=mg+S(2R).
Chapter 13: Thermal Properties of Matter
Key topics: Thermal Expansion, Calorimetry (phase changes, especially with ice), Heat Transfer (Conduction, Newton's Law of Cooling).
Thermal Expansion: L=L0T. Density variation: =-T-3T.
Temperature Scale Conversion: T-LFPUFP-LFP=constant.
Calorimetry: Heat lost = Heat gained. Melting ice (Q=mLf) requires 80cal/g; warming water requires $1\text{ cal/g}^\circ\text{C}$.
Thermal Conduction:
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Parallel: KeffAtotal=K1A1+K2A2.
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Series: LtotalKeff=L1K1+L2K2.
Newton’s Law of Cooling: T1-T2t=kT1+T22-T0. Set up ratio equations to solve for ambient temperature T0.
Class 11 Physics Important Questions
Strengthen your problem-solving speed and numerical accuracy with these high-yield physics questions covering error analysis, 1D and 2D motion, and work-energy relations.
Question 1
In an experiment, the values of two spring constants were measured as k1=(100.2)N/m and k2=(200.3)N/m. If these springs are connected in parallel, what is the percentage error in the equivalent spring constant?
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(a) 1.33%
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(b) 2.67%
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(c) 1.67%
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(d) 2.33%
Question 2
The velocity v and displacement r of a body are related as v2=kr, where k is a constant. What will be the velocity after 1second, given that the displacement is zero at t=0?
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(a) kr
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(b) kr2
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(c) k2r0
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(d) Data is not sufficient
Question 3
A train of length 200m, travelling at 50m/s, overtakes another train of length 130m, travelling at 30m/s. What is the time taken by the first train to pass the second train?
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(a) 15seconds
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(b) 17seconds
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(c) 16.5seconds
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(d) 18seconds
Question 4
A swimmer can swim at a velocity of 12km/h in still water. The water in a river flows at 6km/h. At what angle, with respect to the direction of the river's flow, should the swimmer swim to reach the point directly opposite their starting point on the other bank?
(Round off the answer to the nearest integer.) [16 March 2021 (Shift II)]
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(a) 30
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(b) 120
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(c) 60
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(d) 90
Question 5
A body starts from rest and is acted upon by a constant force. What is the ratio of the kinetic energy gained in the first five seconds to that gained in the next five seconds?
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(a) 2:1
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(b) 1:1
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(c) 3:1
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(d) 1:3
Key Tips to Master Class 11 Physics for NEET
Class 11 Physics forms nearly half of the NEET paper, demanding strong conceptual clarity and quick numerical solving. Here are 5 essential preparation tips:
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Build Strong Mathematical Fundamentals: Master basic calculus (differentiation, integration) and vector resolution first, as they are essential for Mechanics and Kinematics.
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Maintain a Daily Formula Notebook: Keep a separate diary for high-yield formulas, ratio tricks, and shortcut relations across heavy chapters like Rotational Motion and SHM.
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Always Draw Free Body Diagrams (FBD): Sketch clear FBDs for NLM, Friction, and Work-Energy questions to prevent direction and normal reaction errors.
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Use Dimensional Analysis & Elimination: When stuck on complex numericals, check units or substitute extreme boundary values (=0,90) to eliminate wrong options quickly.
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Practice Timed PYQ Sets: Solve previous years' questions within strict time limits (45 questions in 45–50 minutes) to build speed, accuracy, and negative marking control.
Class 11 Physics requires a clear understanding of concepts and regular practice to solve numerical problems accurately. Focus on strengthening fundamental concepts, revising important formulas, solving questions topic-wise, and taking regular mock tests to improve speed and accuracy for NEET. Enrol in Physics Wallah’s NEET Online Batches (Yakeen / Arjuna) for better practice for exam preparati
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