JEE Main: Electric Fields, Heat, and Circular Motion

• JEE MAINS QFT1 2025 is a physics and chemistry-based exam with a mathematics section.
• The maximum marks for the Physics and Chemistry Single Correct sections is 80
• The maximum marks for the Physics Numerical and Chemistry Numerical sections is 20
• The maximum marks for the Mathematics section is 80
• The maximum marks for the Mathematics Numerical section is 20

Electric Fields and Charge

• The electric field in a region is given as E = (E₀/l) * x * î.
• The charge contained inside a cubical volume defined by x=0, x=l, y=0, y=l, z=0, and z=l can be calculated.

Molar Specific Heat of Gases

• For a gas with a molar specific heat of (5/2)R, it isn't specified whether it is Cp or Cv.
• The molecules of the gas can either be monoatomic or rigid diatomic.

Momentum and Kinetic Energy in Circular Motion

• A particle of mass M moves in a horizontal circle of radius R at a uniform speed V.
• When the particle moves to a diametrically opposite point, its momentum changes by 2MV.

Vernier Callipers Measurement

• A Vernier calliper measures the diameter of a steel ball.
• The main scale (MS) has divisions of 0.1 cm, and ten Vernier scale (VS) divisions match nine MS divisions.
• Given three measurements, the mean corrected diameter needs to be determined, considering a zero error of -0.03 cm.

Solid Balls in a Lake

• An iron ball and an aluminum ball of the same diameter are released in a lake.
• The iron ball reaches the bottom first due to its higher density (ρAl < ρFe), neglecting viscosity.

NAND Gate Combinations

• Combinations of NAND gates can create other logic gates.
• Specific arrangements shown are equivalent to other gates.

Double Star Systems

• A double star system includes stars A and B, with time periods TA and TB, radii RA and RB, and masses MA and MB.
• If TA > TB, then RA > RB or MA > MB, the correlation between their time periods, radii and masses may be described by (TA/TB)² = (RA/RB)³.

de Broglie Wavelength and Kinetic Energy

• An electron's de Broglie wavelength at a velocity of 1.5 × 10⁸ m/s equals that of a photon.
• Determining the ratio of the kinetic energy of the electron to that of the photon is possible.

Student Catching a Bus

• A student is 16m away from a bus, which begins to accelerate at 9m/s².
• The minimum velocity (α√2 m/s) the student needs to run to catch the bus can be determined.

Ideal Gas Processes

• An ideal gas transitions from point A to point C on a P-V diagram via processes AOC and ABC.
• Process AOC is isothermal, but the heat requirements for each process are comparable.

Battery and Variable Resistor

• A battery with a 2Ω internal resistance connects to a variable resistor ranging from 4Ω to 10Ω.
• Initially, the resistor is set at 4Ω. It is possible to then determine what happens to the power consumed as the resistance increases.

Error Estimation in 'g' Calculation

• Calculating g from g = 4π²(L/T²) involves errors in measuring L (±2%) and T (±3%).
• The error in the estimated value of g can be determined.

Machine Efficiency and Kinetic Energy

• A machine with 70% efficiency lifts a 10 kg body, using 100 J of energy.
• Upon release, the body's kinetic energy upon reaching the ground can be calculated.

Total Internal Reflection in a Glass Slab

• A light ray strikes a glass slab at 45° from air at point A.
• The minimum refractive index for total internal reflection at point B can be calculated.

Light Beam Force and Intensity

• A light beam exerts 4.8 × 10⁻⁴ N of force on a 0.04 m² surface.
• 80% of the light is absorbed, and the rest is transmitted, and the light intensity can be calculated in W/cm², given the speed of light is 3 × 10⁸ m/s.

Magnetic Properties of Materials

• Four lightweight-rod samples (A, B, C, D) are suspended; a bar magnet is brought near.
• Observations: A is feebly repelled, B is feebly attracted, C is strongly attracted, and D remains unaffected.

Gas Law and Dimensions

• A gas follows the relation PV^(5/3) = K, where P is pressure, V is volume, and K is constant.
• The dimensions of constant K can be determined.

Series LR Circuit

• In a series LR circuit with alternating voltage, inductor voltage is 3V and resistor voltage is 4V when the source voltage is maximum.
• If resistance is 2Ω, the reactance of the inductor can be calculated.

Rotating Wheel

• A wheel's moment of inertia is 2.5 kg-m², with an initial angular velocity of 40 rad/s.
• A 10 Nm torque accelerates it to 60 rad/s, the time for this acceleration can be caculated.

Nuclear Force Properties

• The constancy of binding energy per nucleon in the range 30 < A < 170 results from the short range of nuclear force.
• The nuclear force is independent of nucleon charge and is repulsive at distances less than 0.8 fm between two nucleons.

Open and Closed Organ Pipes

• An open organ pipe is twice the length of a closed one.
• If the open pipe's fundamental frequency is 100Hz, the closed pipe's third harmonic frequency can be determined.

Bead on a Rod in Gravity-Free Space

• In zero gravity, a 1μC charged, 3mg bead threads on a rough rod (μ = 0.3).
• A 0.2T magnetic field is perpendicular, and the bead is projected at 4m/s; the distance it covers before stopping can be calculated.

Proton Approaching a Nucleus

• A proton is shot at a nucleus with charge Q = 120e from afar, approaching within 10 fm.
• The proton's de Broglie wavelength at the start can be calculated by accounting for its mass.

Rotating Coil in Magnetic Field

• A 0.01 m² circular coil with 40 turns rotates at 50 rad/s in a 0.05T magnetic field.
• With a 25 mW average power loss from Joule heating, the closed-loop resistance can be calculated.

Block-Spring System Collision

• A 0.3 kg block connected to a spring (constant k) is compressed and released.
• After moving half the equilibrium distance which is (x/2), it hits another block and proceed at 2 m/s, and the spring's initial energy can be found.

Tollen's Reagent and Disaccharides

• Disaccharides may or may not reduce Tollen's reagent.
• The key is to identify which of the disaccharides will not do so.

Dehydration and Aromaticity

• Elimination reactions will result in the preferred major product
• A non-aromatic compound has differing properties to an aromatic compound, and the nature of their properties can be determined..

Complex Compounds and Chloride Precipitation

• For a complex MCl₃⋅4H₂O with a coordination number of six, but no hydration molecules, 200 mL of 0.01 M solution requires a certain volume of 0.1 M AgNO₃ to precipitate free chloride ions.

Electrochemical Cell and Gibbs Free Energy

• In the cell Zn(s)|ZnSO₄(aq)||CuSO₄(aq)|Cu(s), with [Zn²⁺] = 10[Cu²⁺], the expression for ΔG in J/mol is determinable.

Molecular Geometry and VSEPR Theory

• The relationship between molecular structures and geometry should be considered.
• Molecular geometry include V-Shaped, Triangular Planar ,Trigonal Bipyramidal, Trigonal Pyramidal and Tetrahedral.

Nickel Complex Ions

• The green colored complex ion of nickel in aqueous solution can be one of the follwing: [Ni(en)3]2+, [Ni(H2O)2(en)2]2+, [Ni(H2O)4(en)]2+, [Ni(H2O)6]2+
• The specific ion can be determined.

Benzene Combustion Stoichiometry

• The litres of oxygen needed (at STP) to completely burn 39g of liquid benzene can be determined.

List Matching - Isomerism

• Matching different types of isomerism.
• Includes Metamerism, Cis-trans isomerism,Optical isomerism ,Conformational isomerism ,Dynamic isomerism/Tautomerism

Silicon Halide Formation

• Existence of [SiF₆]²⁻ versus non-existence of [SiCl₆]²⁻ is an assertion.
• Electronegativity difference between F and Cl has bearing on relative stability; whether it acts as the reason, and whether assertion holds needs verification.

Organic Compound A with Dichromate

• An organic compound (C6H12O) will not decolorise the orange-red acidic potassium dichromate, reacts with H₂SO₄ yielding alkene, will further react yielding C6H10O3
• Identification of structure of given substance/molecule is crucial.

Trimethylamine vs Trisilylamine

• How their molecular structure is different based on which base atom is being used.
• Trimethylamine in pyramidal, whereas trisilylamine is a planar molecule. Why the difference arise.

Complex normality

• Complex normality [Cr(H₂O)₅Cl]Cl₂⋅H₂O given, it goes through cation exterminator and the HCl formed is dilated to 1L
• Normality Calculation is the focus.

equilibrium constant

• Give reactions and one corresponding, finding the other equilibrium constant is asked.
• SO₂ (g) + 𝟏/₂ O₂ (g) ⇌ SO₃ (g) with value = 5 × 10⁻² atm and 2SO₃ (g) ⇌ 2SO₂ (g) + O₂ (g) with vlaue = ?

Paramagnetic Nature of Complexes

• Identify the number of inner orbital complexes paramagnetic.
• [Mn(CN)6]3−​, [Fe(CN)6]3−​, [Co(C2O4)3]3−​, [MnCl6]3−​, [Fe(CN)6]4−​, [CoF6]3−​