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![Chlorobenzene reacting with (i) NaOH, 623 K, 300 atm then Na₂Cr₂O₇/H₂SO₄ to form [A], then (ii) H⁺ to form [B]](/api/qna-image?path=QnA%2Fb65cda62-f924-480b-b4db-1d3aaa6069d4%2F5ef15551-aed6-4f93-a8d5-a219b7a5d19b%2F0ae0751d-b12b-4f4d-b4ac-2ec0991fedb8%2F0ae0751d-b12b-4f4d-b4ac-2ec0991fedb8%2Fimages%2FQQ51_A.webp)






JEE Main 2025 January 23, Shift 2 Question Paper with Solutions
All 75 questions from the JEE Main 2025 (January 23, Shift 2) shift — Physics (25), Chemistry (25) and Mathematics (25) — with the correct answer and a step-by-step solution for every question.
Physics25 questions
Q26Single correctMagnetic Effects of Current and Magnetism
A galvanometer having a coil of resistance need 20 mA of current for full-scale deflection. If a maximum current of 3 A is to be measured using this galvanometer, the resistance of the shunt to be added to the galvanometer should be , where X is
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2149
Approach:
Use the shunt resistance formula for converting a galvanometer to an ammeter. The shunt resistance is calculated using the current division rule where most of the current passes through the shunt.
Step 1:Identify given values: galvanometer resistance G = 30Ω, galvanometer current = 20 mA = 0.02 A, maximum current I = 3 A
Step 2:Apply shunt resistance formula
Step 3:Calculate the shunt resistance
Step 4:Compare with given form to find X
Final answer: The value of X is 149
Q27Single correctKinematics
A ball having kinetic energy KE, is projected at an angle of from the horizontal. What will be the kinetic energy of ball at the highest point of its flight?
(A)
(B)
(C)
(D)
SolutionAnswer: Option 4
Approach:
At the highest point of projectile motion, the vertical component of velocity becomes zero, only horizontal component remains. Calculate the kinetic energy using horizontal component of initial velocity.
Step 1:Express initial kinetic energy in terms of initial velocity
Step 2:Find horizontal component of velocity for angle 60°
Step 3:Calculate kinetic energy at highest point using horizontal velocity
Step 4:Express in terms of initial KE
Final answer: The kinetic energy at the highest point is KE/4
Q28Single correctElectrostatics
Two charges and are placed at and respectively. Given, , the electrostatic potential energy of the charge configuration is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1-1.8 J
Approach:
Calculate the electrostatic potential energy of two point charges using the formula U = kq₁q₂/r, where k = 1/(4πε₀) and r is the distance between charges.
Step 1:Identify the charges and their positions
Step 2:Calculate distance between charges
Step 3:Apply potential energy formula
Step 4:Calculate the potential energy
Final answer: The electrostatic potential energy is -1.8 J
Q29Single correctElectrostatics
Two point charges and , constituting an electric dipole, are placed at and in a uniform electric field of strength . The work done on the dipole in rotating it from the equilibrium through is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 214.4 mJ
Approach:
Calculate work done in rotating a dipole in uniform electric field using W = pE(cosθ₁ - cosθ₂), where p is dipole moment, E is electric field, and angles are measured from equilibrium position.
Step 1:Calculate the dipole moment
Step 2:Identify the electric field strength
Step 3:Apply work done formula for 180° rotation from equilibrium
Step 4:Calculate the work done
Final answer: The work done on the dipole is 14.4 mJ
Q30Single correctProperties of Solids and Liquids
A massless spring gets elongated by amount under a tension of 5 N. Its elongation is under the tension of 7 N. For the elongation of , the tension required is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 311 N
Approach:
Use Hooke's law F = kx to establish relationship between force and elongation. Find spring constant k using given conditions, then calculate force for the required elongation.
Step 1:Apply Hooke's law for first condition
Step 2:Apply Hooke's law for second condition
Step 3:Equate both expressions to find relation between x₁ and x₂
Step 4:Calculate the elongation (5x₁ - 2x₂)
Step 5:Calculate force for this elongation
Final answer: The tension in the spring for elongation (5x₁ - 2x₂) is 11 N
Q31Single correctThermodynamics
Water of mass m gram is slowly heated to increase the temperature from to . The change in entropy of the water, given specific heat of water is , is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1
Approach:
Calculate entropy change using the formula ΔS = ∫(dQ/T) for reversible heating process. For constant specific heat, this integrates to ΔS = mc ln(T₂/T₁).
Step 1:Write entropy change formula for reversible process
Step 2:Express heat in terms of specific heat and temperature change
where
Step 3:Substitute and integrate
Step 4:Evaluate the integral
Step 5:Substitute c = 1 J kg⁻¹ K⁻¹ and convert mass to kg (m grams = m/1000 kg, but given answer suggests m is treated as dimensionless coefficient)
Final answer: The change in entropy is m ln(T₂/T₁)
Q32Single correctProperties of Solids and Liquids
Water flows in a horizontal pipe whose one end is closed with a valve. The reading of the pressure gauge attached to the pipe is . The reading of the pressure gauge falls to when the valve is opened. The speed of water flowing in the pipe is proportional to
(A)
(B)
(C)
(D)
SolutionAnswer: Option 4
Approach:
Apply Bernoulli's equation for horizontal pipe flow. When valve is closed, water is at rest (v=0, P=P₁). When valve opens, water flows with velocity v and pressure drops to P₂.
Step 1:Apply Bernoulli's equation for horizontal pipe when valve is closed
Step 2:Apply Bernoulli's equation when valve is open
Step 3:Equate both expressions (same horizontal level)
Step 4:Solve for velocity v
Step 5:Take square root to get velocity
Final answer: The speed of water is proportional to √(P₁ - P₂)
Q33Single correctOptics
A concave mirror of focal length f in air is dipped in a liquid of refractive index . Its focal length in the liquid will be:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2
Approach:
For mirrors, the focal length depends only on the geometry (radius of curvature) and not on the refractive index of the surrounding medium. This is because reflection laws do not depend on the medium.
Step 1:Recall the mirror equation and focal length relation
where R is radius of curvature
Step 2:Note that law of reflection is independent of medium
holds in any medium
Step 3:Analyze effect of refractive index on mirrors
Mirror focal length: (no dependence)
Step 4:Conclude that focal length remains same
Final answer: The focal length of the concave mirror in liquid remains f (unchanged)
Q34Single correctCurrent Electricity
What is the current through the battery in the circuit shown below

(A)
(B)
(C)
(D)
SolutionAnswer: Option 20.5
Approach:
Calculate equivalent resistance of parallel resistors and apply Ohm's law to find the current through the battery.
Step 1:Identify the circuit configuration
in parallel,
Step 2:Calculate equivalent resistance for parallel combination
Step 3:Apply Ohm's law to find total current
Final answer: [object Object]
Q35Single correctOptics
The refractive index of the material of a glass prism is . The angle of minimum deviation is equal to the angle of the prism. What is the angle of the prism?
(A)
(B)
(C)
(D)
SolutionAnswer: Option 160^
Approach:
Use the prism formula relating refractive index to prism angle and minimum deviation. Given that minimum deviation equals prism angle, simplify and solve for A.
Step 1:Write the prism formula at minimum deviation
Step 2:Substitute δ_m = A into the formula
Step 3:Apply the double angle identity for sine
Step 4:Simplify and solve for cos(A/2)
Step 5:Find the prism angle
Final answer: [object Object]
Q36Single correctOptics
The width of one of the two slits in Young's double slit experiment is d while that of the other slit is xd. If the ratio of the maximum to the minimum intensity in the interference pattern on the screen is 9:4 then what is the value of x? (Assume that the field strength varies according to the slit width.)
(A)
(B)
(C)
(D)
SolutionAnswer: Option 25
Approach:
Field amplitude is proportional to slit width. Use the intensity ratio formula for interference to find the width ratio x.
Step 1:Establish amplitude-width relationship
Step 2:Express intensity ratio in terms of amplitudes
Step 3:Take square root and substitute A₂ = xA₁
Step 4:Solve for x (assuming x > 1 since second slit is wider)
Final answer: [object Object]
Q37Single correctThermodynamics
Using the given P-V diagram, the work done by an ideal gas along the path ABCD is:

(A)
(B)
(C)
(D)
SolutionAnswer: Option 3-
Approach:
Calculate work done in each segment of the P-V diagram. Work done equals area under the curve in P-V diagram.
Step 1:Work done in path AB (isobaric expansion at pressure P₀)
Step 2:Work done in path BC (isochoric process at constant volume 3V₀)
Step 3:Work done in path CD (isobaric compression at pressure 2P₀)
Step 4:Work done in path DA (isochoric process at constant volume V₀)
Step 5:Total work along ABCD
Final answer: [object Object]
Q38Single correctElectromagnetic Waves
A plane electromagnetic wave of frequency 20 MHz travels in free space along the +x direction. At a particular point in space and time, the electric field vector of the wave is . The magnetic field vector of the wave is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2 = 3.1
Approach:
In an electromagnetic wave, E and B are related by E = cB. Use the right-hand rule to determine the direction of B given E and propagation direction.
Step 1:Write the relation between E and B in an EM wave
where
Step 2:Calculate the magnetic field magnitude
Step 3:Determine direction using right-hand rule (E × B || propagation)
points in +x direction, is in y-direction is in z-direction
Final answer: [object Object]
Q39Single correctOscillations and Waves
The equation of a transverse wave travelling along a string is , where x is in mm and t is in second. The velocity of the wave is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2-30
Approach:
Identify wave equation form and extract wave parameters. The sign of (kx + ωt) indicates negative x-direction propagation.
Step 1:Identify the wave equation form and direction
represents wave traveling in negative x-direction (+ sign means opposite to +x)
Step 2:Extract wave parameters from the equation
,
Step 3:Calculate wave velocity magnitude and apply direction
, direction is -x
Final answer: [object Object]
Q40Single correctAtoms and Nuclei
Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The binding energy per nucleon is found to be practically independent of the atomic number A, for nuclei with mass numbers between 30 and 170. Reason (R): Nuclear force is long range. In the light of the above statements, choose the correct answer from the options given below:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1
Approach:
Evaluate the truth of both assertion and reason independently, then determine their relationship.
Step 1:Evaluate Assertion (A)
Step 2:Evaluate Reason (R)
Step 3:Determine the correct option
Final answer: [object Object]
Q41Single correctGravitation
If a satellite orbiting the Earth is 9 times closer to the Earth than the Moon, what is the time period of rotation of the satellite? Given rotational time period of Moon = 27 days and gravitational attraction between the satellite and the moon is neglected.
(A)
(B)
(C)
(D)
SolutionAnswer: Option 21
Approach:
Apply Kepler's third law relating orbital period to orbital radius. Satellite at = /9 will have period calculated using T² ∝ R³.
Step 1:Apply Kepler's third law for both satellite and Moon
Step 2:Substitute = /9 (satellite is 9 times closer)
Step 3:Solve for satellite's time period
Final answer: [object Object]
Q42Single correctRotational Motion
A circular disk of radius R meter and mass M kg is rotating around the axis perpendicular to the disk. An external torque is applied to the disk such that , where is the angular position of the rotating disc as a function of time t. How much power is delivered by the applied torque, when ?
(A)
(B)
(C)
(D)
SolutionAnswer: Option 4
Approach:
Find angular velocity and acceleration by differentiating θ(t). Calculate torque using τ = Iα and power using P = τω.
Step 1:Find angular velocity by differentiating θ(t)
Step 2:Find angular acceleration
Step 3:Calculate moment of inertia for the disk
Step 4:Calculate applied torque
Step 5:Calculate power delivered at t = 2s
Final answer: [object Object]
Q43Single correctUnits and Measurements
The energy of a system is given as , where t is the time and . The errors in the measurement of and t are % and 1.6%, respectively. At , maximum percentage error in the energy is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1
Approach:
Given where , , error in is and error in t is . Taking natural logarithm: . Differentiating: . Maximum percentage error: .
Step 1:Take natural logarithm of energy equation
E = 3 t
Step 2:Differentiate to find error propagation
= 3 t
Step 3:Substitute values
= 3(0.012) + 0.3(0.016 5) = 0.036 + 0.024 = 0.06 = 6%
Final answer: [object Object]
Q44Single correctUnits and Measurements
Match List - I with List - II.
| List - I | List - II |
|---|---|
| A. Permeability of free space | I. |
| B. Magnetic field | II. |
| C. Magnetic moment | III. |
| D. Torsional constant | IV. |
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2(A)-(III), (B)-(II), (C)-(IV), (D)-(I)
Approach:
Matching dimensions: (A) Permeability has dimensions (III). (B) Magnetic field B has dimensions (II). (C) Magnetic moment m has dimensions (IV). (D) Torsional constant has dimensions (I).
Step 1:Determine dimensions of permeability of free space
Step 2:Determine dimensions of magnetic field
Step 3:Determine dimensions of magnetic moment
]
Step 4:Determine dimensions of torsional constant
]
Final answer: [object Object]
Q45Single correctDual Nature of Matter and Radiation
In photoelectric effect an em-wave is incident on a metal surface and electrons are ejected from the surface. If the work function of the metal is and stopping potential is , what is the wavelength of the em-wave? (Given where h is the Planck's constant and c is the speed of light in vacuum.)
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1300 \,
Approach:
Using Einstein's photoelectric equation: where , (work function), and (stopping potential). Therefore: . Solving for : .
Step 1:Apply Einstein's photoelectric equation
Step 2:Calculate total photon energy
E = 2.14 + 2.0 = 4.14 \,
Step 3:Calculate wavelength using energy-wavelength relation
= 300 \,
Final answer: [object Object]
Q46NumericalElectromagnetic Induction and Alternating Currents
A time varying potential difference is applied between the plates of a parallel plate capacitor of capacitance . The dielectric constant of the medium is 5. The current is:
SolutionAnswer: 100
Approach:
Displacement current is given by where and . Therefore: .
Step 1:Apply displacement current formula
= C
Step 2:Rearrange to find rate of change of voltage
Step 3:Substitute values
Final answer: [object Object]
Q47NumericalElectromagnetic Induction and Alternating Currents
In a series LCR circuit, a resistor of , a capacitor of and an inductor of are used. The angular frequency at resonance is:
SolutionAnswer: 2
Approach:
For maximum current in LCR circuit, resonance condition is where and . Therefore: . Answer is 2.
Step 1:Apply resonance condition for LCR circuit
Step 2:Substitute values
Step 3:Calculate angular frequency
Final answer: [object Object]
Q48NumericalProperties of Solids and Liquids
An air bubble of radius is observed at a depth of below the free surface of a liquid having surface tension and density . The difference in pressure is:
SolutionAnswer: 2150
Approach:
Calculate total pressure difference as sum of hydrostatic pressure and excess pressure due to surface tension. For an air bubble in liquid, excess pressure is 2T/r (single interface).
Step 1:Identify given values
Step 2:Calculate hydrostatic pressure at depth h
Step 3:Calculate excess pressure due to surface tension (air bubble in liquid has single interface)
Step 4:Calculate total pressure difference
Final answer: [object Object]
Q49NumericalGravitation
A satellite of mass is revolving around earth in a circular orbit at a height of from earth surface. The angular momentum of the satellite is . The value of x is ______, where M and R are the mass and radius of earth, respectively. (G is the gravitational constant)
SolutionAnswer: 3
Approach:
Orbital radius . Orbital velocity . Angular momentum . Therefore .
Step 1:Calculate orbital radius
r = R +
Step 2:Calculate orbital velocity
Step 3:Calculate angular momentum
Final answer: [object Object]
Q50NumericalCurrent Electricity
At steady state the charge on the capacitor, as shown in the circuit below, is _____ .
SolutionAnswer: 16
Approach:
At steady state, the capacitor acts as an open circuit. From the circuit configuration, the 10 Ω and 15 Ω resistors form a voltage divider. If the capacitor is parallel to the 10 Ω resistor, the voltage across it is . Charge on capacitor: .
Step 1:Identify circuit configuration at steady state
Step 2:Calculate voltage across 10 Ω resistor using voltage divider
5 = 5 = 2 \,
Step 3:Calculate charge on capacitor
Q = CV = 8 2 = 16 \, = 16 \,
Final answer: [object Object]
Chemistry25 questions
Q51Single correctOrganic Compounds Containing Oxygen
Identify the products [A] and [B], respectively in the following reaction:
![Chlorobenzene reacting with (i) NaOH, 623 K, 300 atm then Na₂Cr₂O₇/H₂SO₄ to form [A], then (ii) H⁺ to form [B]](/api/qna-image?path=QnA%2Fb65cda62-f924-480b-b4db-1d3aaa6069d4%2F5ef15551-aed6-4f93-a8d5-a219b7a5d19b%2F0ae0751d-b12b-4f4d-b4ac-2ec0991fedb8%2F0ae0751d-b12b-4f4d-b4ac-2ec0991fedb8%2Fimages%2FQQ51_A.webp)
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2Phenol and p-benzoquinone
Approach:
Identify products from nucleophilic aromatic substitution followed by oxidation reaction sequence
Step 1:Chlorobenzene reacts with NaOH at high temperature and pressure (623 K, 300 atm) in nucleophilic aromatic substitution to form sodium phenoxide, which upon acidification gives phenol as intermediate [A]
Step 2:Phenol undergoes oxidation with acidified Na₂Cr₂O₇ (strong oxidizing agent) to form p-benzoquinone
Step 3:The reaction sequence shows nucleophilic aromatic substitution followed by oxidation, producing phenol intermediate and p-benzoquinone as final product
Final answer: [object Object]
Q52Single correctd- and f-Block Elements
Consider the following reactions: . The sum of spin only magnetic moments of the compounds A and B is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3
Approach:
Identify products of chromate-dichromate equilibrium under basic and acidic conditions
Step 1:Potassium dichromate reacts with KOH in basic medium, converting dichromate ion to chromate ion
Step 2:Potassium chromate reacts with H₂SO₄ in acidic medium, converting back to dichromate
Step 3:This is the classic chromate-dichromate equilibrium: chromate (yellow) in base, dichromate (orange) in acid
Final answer: [object Object]
Q53Single correctChemical Thermodynamics
The effect of temperature on spontaneity of reactions are represented as:

(A)
(B)
(C)
(D)
SolutionAnswer: Option 1(B) and (C) only
Approach:
Use Gibbs free energy equation to analyze spontaneity criteria for different sign combinations of ΔH and ΔS at various temperatures
Step 1:For spontaneity, ΔG must be negative. Using Gibbs equation: ΔG = ΔH - TΔS
G = H - T S < 0
Step 2:Case (A): ΔH = +, ΔS = -, any T. ΔG = (+) - T(-) = (+) + T(+) = always positive, never spontaneous
G = (+) - T(-) > 0
Step 3:Case (B): ΔH = +, ΔS = +, low T. At low T, TΔS term is small, so ΔG = (+) - (small +) > 0, non-spontaneous. But labeled as spontaneous at low T - this is INCORRECT
G = (+) - T(+) > 0
Step 4:Case (C): ΔH = -, ΔS = -, low T. At low T, TΔS is small, so ΔG = (-) - (small -) = (-) + (small +) < 0, spontaneous at low T. Labeled as non-spontaneous - INCORRECT
G = (-) - T(-) < 0
Step 5:Case (D): ΔH = -, ΔS = +, any T. ΔG = (-) - T(+) = (-) - (+) = always negative, always spontaneous
G = (-) - T(+) < 0
Step 6:Rows (B) and (C) show INCORRECT temperature-spontaneity relationships
Final answer: [object Object]
Q54Single correctChemical Kinetics
Which of the following graphs most appropriately represents a zero order reaction?
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1Linear decrease of Reactant Concentration vs Time
Approach:
Apply zero order kinetics integrated rate law to identify characteristic concentration vs time graph
Step 1:For zero order reaction, rate is independent of concentration
= k = k =
Step 2:The integrated rate law for zero order reaction shows linear relationship between concentration and time
[A] = - kt
Step 3:Graph of [Reactant] vs time for zero order is a straight line with negative slope (-k)
= -k, =
Step 4:Option (1) shows linear decrease of reactant concentration vs time, which is characteristic of zero order reaction
[A] t
Final answer: [object Object]
Q55Single correctEquilibrium
Consider the reaction . The equation representing correct relationship between the degree of dissociation (x) of and equilibrium constant () is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2
Approach:
Set up ICE table for dissociation equilibrium and derive relationship between degree of dissociation and Kp
Step 1:Set up ICE table. Initial: X₂Y = p atm, products = 0. At equilibrium with degree of dissociation x
Step 2:Write Kp expression
Step 3:Since x is very small, (1-x) ≈ 1
Step 4:Simplify further
Step 5:Solve for x
Step 6:Simplify to match options
Final answer: [object Object]
Q56Single correctOrganic Compounds Containing Oxygen
Given below are two statements: Consider the following reaction for hydration of aldehydes and ketones.

(A)
(B)
(C)
(D)
SolutionAnswer: Option 4Both Statement I and Statement II are true
Approach:
Analyze hydration equilibrium of carbonyl compounds based on electronic and steric factors
Step 1:Statement I: Formaldehyde (HCHO) has small H substituents with no steric hindrance and no electron-donating groups, making the carbonyl carbon highly electrophilic
Step 2:Statement II: Trichloroacetaldehyde (CCl₃CHO) has three -Cl groups with strong -I effect, withdrawing electrons and making carbonyl carbon more electrophilic, favoring nucleophilic attack by water
Step 3:Both statements correctly explain why these aldehydes have high hydration equilibrium constants
Final answer: [object Object]
Q57Single correctAtomic Structure
Given below are two statements: Statement (I): For a given shell, the total number of allowed orbitals is given by n². Statement (II): For any subshell, the spatial orientation of the orbitals is given by -l to +l values including zero. In the light of the above statements, choose the correct answer from the options given below:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3Both Statement I and Statement II are true
Approach:
Verify quantum number rules for orbital count and spatial orientations
Step 1:Statement I: For principal quantum number n, l ranges from 0 to (n-1), and for each l, ml ranges from -l to +l (total 2l+1 orbitals)
_
Step 2:Statement II: For azimuthal quantum number l, magnetic quantum number ml ranges from -l to +l including zero, giving (2l+1) orientations
)
Step 3:Both statements are fundamental principles of quantum mechanics and atomic structure
Final answer: [object Object]
Q58Single correctRedox Reactions and Electrochemistry
Standard electrode potentials for a few half cells are mentioned below: , , . The galvanic cell that gives the highest voltage is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1|)|
Approach:
Calculate cell potential for each galvanic cell combination and identify the one with highest voltage (most negative ΔG°)
Step 1:Relationship between cell potential and Gibbs energy
}
Step 2:Calculate E°cell for option (1): Zn|Zn²⁺||Ag⁺|Ag
Step 3:Calculate E°cell for option (2): Zn|Zn²⁺||Mg²⁺|Mg
} = -2.37 - (-0.76) = -1.61 )
Step 4:Calculate E°cell for option (3): Ag|Ag⁺||Mg²⁺|Mg
} = -2.37 - 0.80 = -3.17 )
Step 5:Calculate E°cell for option (4): Cu|Cu²⁺||Ag⁺|Ag
} = 0.80 - 0.34 = 0.46
Step 6:Compare all viable options: Option (1) gives -3.12F, Option (4) gives -0.92F
G° = -3.12F
Final answer: [object Object]
Q59Single correctBiomolecules
The -Helix and -Pleated sheet structures of protein are associated with its:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3secondary structure
Approach:
Identify the level of protein structure associated with α-helix and β-pleated sheet conformations
Step 1:Identify protein structure levels
Step 2:Recognize secondary structure characteristics
Step 3:Conclude the structure level
Final answer: [object Object]
Q60Single correctp-Block Elements
Given below are the atomic numbers of some group 14 elements. The atomic number of the element with lowest melting point is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 450
Approach:
Compare melting points of Group 14 elements to identify the one with lowest melting point
Step 1:Identify Group 14 elements by atomic number
Step 2:Compare melting points of Group 14 elements
Step 3:Identify the element with lowest melting point
Final answer: [object Object]
Q61Single correctAtomic Structure
Given below are two statements about X-ray spectra of elements: Statement (I): A plot of (v = ) vs atomic mass is a straight line. Statement (II): A plot of v (v = ) vs atomic number is a straight line. In the light of the above statements, choose the correct answer from the options given below:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3
Approach:
Apply Moseley's law to evaluate statements about X-ray spectra relationships
Step 1:Recall Moseley's law for X-ray spectra
= a(Z - b) v Z a, b
Step 2:Evaluate Statement I
Step 3:Evaluate Statement II
v Z Z v Z
Final answer: [object Object]
Q62Single correctPrinciples Related to Practical Chemistry
Identify A, B and C in the given below reaction sequence: .
(A)
(B)
(C)
(D)
SolutionAnswer: Option 4
Approach:
Identify lead compounds through sequential reactions with nitric acid, sulfuric acid, and chromate
Step 1:Determine compound A from the first reaction
Step 2:Determine compound B from the second reaction
Step 3:Determine the final product C
Final answer: [object Object]
Q63Single correctOrganic Compounds Containing Oxygen
Given below are two statements: Statement (I): The boiling points of alcohols and phenols increase with increase in the number of C-atoms. Statement (II): The boiling points of alcohols and phenols are higher in comparison to other class of compounds such as ethers, haloalkanes. In the light of the above statements, choose the correct answer from the options given below:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2
Approach:
Analyze boiling point trends based on molecular size and hydrogen bonding capability
Step 1:Evaluate Statement I
Step 2:Evaluate Statement II
Step 3:Conclude
Final answer: [object Object]
Q64Single correctSolutions
Consider a binary solution of two volatile liquid components 1 and 2. and are the mole fractions of component 1 in liquid and vapour phase, respectively. The slope and intercept of the graph are:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2
Approach:
Derive linear relationship between 1/y₁ and 1/x₁ using Raoult's law for binary volatile solutions
Step 1:Apply Raoult's law for binary volatile solution
Step 2:Rearrange to get linear form
= 1 +
Step 3:Express in terms of 1/x₁
Final answer: [object Object]
Q65Single correctOrganic Compounds Containing Halogens
The ascending order of relative rate of solvolysis of following compounds is:

(A)
(B)
(C)
(D)
SolutionAnswer: Option 2(D) < (A) < (B) < (C)
Approach:
Order compounds by solvolysis rate based on carbocation stability in SN1 mechanism
Step 1:Identify the mechanism and rate-determining factor
Step 2:Analyze carbocation stability for each structure
Step 3:Order by increasing carbocation stability
Final answer: [object Object]
Q66Single correctd- and f-Block Elements
Match List - I with List - II.
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2(A)-(IV), (B)-(III), (C)-(I), (D)-(II)
Approach:
Match alloys with their metal compositions based on standard alloy definitions
Step 1:Identify composition of Bronze
(A)-(IV)
Step 2:Identify composition of Brass
(B)-(III)
Step 3:Identify composition of UK silver coin
(C)-(I)
Step 4:Identify composition of Stainless steel
(D)-(II)
Final answer: [object Object]
Q67Single correctHydrocarbons
Match List - I with List - II.
| Isomers of C₁₀H₁₄ | Ozonolysis product |
|---|---|
| (A) | (I) |
| (B) | (II) |
| (C) | (III) |
| (D) | (IV) |

(A)
(B)
(C)
(D)
SolutionAnswer: Option 3(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
Approach:
Match aromatic isomers with their ozonolysis products by analyzing C=C bond cleavage patterns
Step 1:Identify the structural isomers of C₁₀H₁₄ shown in List-I, which are cyclic aromatic compounds with different substitution patterns
Step 2:Analyze the ozonolysis products shown in List-II, which are dicarbonyl compounds formed by cleaving C=C double bonds
Step 3:Match each isomer with its corresponding ozonolysis product by analyzing which C=C bonds would be cleaved
Final answer: [object Object]
Q68Single correctEquilibrium
pH of water is 7 at . If water is heated to , its pH will:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1
Approach:
Apply Le Chatelier's principle to water ionization equilibrium to determine pH change with temperature
Step 1:Recall that the ionization of water is an endothermic process
Step 2:Apply Le Chatelier's principle: increasing temperature favors the forward reaction, increasing both [H⁺] and [OH⁻]
= [H^+][OH^-]
Step 3:Since [H⁺] increases, pH = -log[H⁺] decreases
pH = -[H^+] [H^+]
Step 4:Note that water remains neutral (H⁺ = OH⁻) even though pH < 7 at higher temperature
80^ C: pH < 7
Final answer: [object Object]
Q69Single correctCoordination Compounds
Identify the coordination complexes in which the central metal ion has configuration.

(A)
(B)
(C)
(D)
SolutionAnswer: Option 3(B) (D)
Approach:
Determine oxidation states and d-electron configurations to identify d⁴ complexes
Step 1:Determine the oxidation state and d-electron configuration for each metal ion
Step 2:Identify complexes with d⁴ configuration
Step 3:Verify the electron configurations
Mn: [Ar] Cr: [Ar]
Final answer: [object Object]
Q70Single correctSolutions
(A)
(B)
(C)
(D)
SolutionAnswer: Option 40.6
Approach:
Use Raoult's law to relate vapour pressure lowering to mole fraction and calculate solvent mole fraction
Step 1:Apply Raoult's law for relative lowering of vapour pressure
Step 2:For the first case with 10 mm Hg decrease
= 0.2 = 50
Step 3:For the second case with 20 mm Hg decrease
Step 4:Calculate mole fraction of solvent
Final answer: [object Object]
Q71NumericalSome Basic Concepts in Chemistry
mole of an organic compound (X) containing % hydrogen, on complete combustion produced . Molar mass of X is:
SolutionAnswer: 100
Approach:
Calculate molar mass from combustion data using hydrogen percentage and water produced
Step 1:Calculate moles of H₂O produced
= 0.05
Step 2:Calculate moles of H atoms in the compound
Step 3:Calculate mass of hydrogen in the compound
Step 4:Since H is 10% of the compound, calculate total mass
Step 5:Calculate molar mass
Final answer: [object Object]
Q72NumericalHydrocarbons
A compound 'X' absorbs 2 moles of hydrogen and 'X' upon oxidation with gives , . The compound X is:

SolutionAnswer: 27
Approach:
Reconstruct diene structure from oxidation products and count sigma bonds
Step 1:Analyze the oxidation products: acetone, acetic acid, and adipic acid derivatives
COOH,
Step 2:Work backwards to determine structure of X before oxidation, which contains 2 C=C bonds (absorbs 2 mol H₂)
X
Step 3:Reconstruct compound X structure based on oxidation products
X: -C=CH--C=CCH_3
Step 4:Count sigma bonds in compound X: C-C single bonds, C-H bonds, and sigma bonds within C=C
8(C-C) + 16(C-H) + 2( C=C) = 27
Final answer: [object Object]
Q73NumericalSome Basic Concepts in Chemistry
When of aluminium is allowed to react with of oxygen gas, the mass of aluminium oxide produced in grams is _____.
SolutionAnswer: 153
Approach:
Apply stoichiometry with limiting reagent analysis to calculate product mass
Step 1:Write balanced chemical equation
4Al +
Step 2:Calculate moles of Al and O₂
= 3.0 = 4.0
Step 3:Identify limiting reagent using stoichiometric ratio
, ,
Step 4:Calculate moles of Al₂O₃ produced
2 = 1.5
Step 5:Calculate mass of Al₂O₃
Final answer: [object Object]
Q74NumericalChemical Thermodynamics
The bond dissociation enthalpy of , , calculated from the given data is _____ . (Nearest integer). , . , . , . , . , . [Given: is a pure ionic compound and X forms a diatomic molecule in gaseous state]
SolutionAnswer: 200
Approach:
Apply Born-Haber cycle using Hess's law to calculate unknown bond dissociation enthalpy from given thermochemical data
Step 1:Apply Born-Haber cycle and Hess's law
Step 2:Substitute the given values
Step 3:Simplify and solve for bond dissociation enthalpy
Step 4:Calculate the bond dissociation enthalpy
Final answer: [object Object]
Q75NumericalOrganic Compounds Containing Nitrogen
Consider the following sequence of reactions. Total number of hybridised carbon atoms in the major product C formed is _____.

SolutionAnswer: 4
Approach:
Trace through diazotization, azo coupling, and Williamson ether synthesis to identify final product structure and count sp³ hybridized carbons
Step 1:First step: Diazotization of p-ethoxyaniline with NaNO₂/HCl at 0-5°C
Step 2:Second step: Azo coupling with phenol in NaOH to form azo dye B (C₁₄H₁₄N₂O₂)
Step 3:Third step: Williamson ether synthesis to convert phenolic -OH to ether, forming C (C₁₆H₁₈N₂O₂)
Step 4:Count sp³ hybridized carbons in C: Left ethoxy (-OCH₂CH₃) has 2 sp³ C, Right ethoxy (-OCH₂CH₃) has 2 sp³ C
Final answer: [object Object]
Mathematics25 questions
Q1Single correctThree Dimensional Geometry
The distance of the line from the point along the line is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3
Approach:
Find intersection of two lines in 3D space, then calculate distance from given point to intersection point.
Step 1:Write parametric form of line L₁
Step 2:Write parametric form of line L₂ and verify given point lies on it
, Point:
Step 3:Set up equations for intersection of L₁ and L₂
... (1), ... (2), ... (3)
Step 4:Substitute equation (1) into equation (2)
Step 5:Find t from equation (1)
Step 6:Verify with equation (3)
and
Step 7:Find intersection point using t=2 in L₂
Point
Step 8:Calculate distance from (1, 4, 0) to (2, 6, 3)
Final answer: [object Object]
Q2Single correctSets, Relations and Functions
Let and . If , then is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 4
Approach:
Find points in the intersection of sets A and B that lie on coordinate axes, then sum |x+y| values.
Step 1:Understand set A: region where |x+y| ≥ 3
: Points outside the band between lines and
Step 2:Understand set B: diamond region
: Diamond with vertices at
Step 3:Find points on y=0 (x-axis) in A∩B
On : B requires , A requires
Step 4:Calculate |x+y| for points on x-axis
;
Step 5:Find points on x=0 (y-axis) in A∩B
On : B requires , A requires
Step 6:Calculate |x+y| for points on y-axis
;
Step 7:Total sum
Final answer: [object Object]
Q3Single correctSets, Relations and Functions
Let . Define a relation R on X as: . Statement I: R is an equivalence relation. Statement II: For some , the set represents a line parallel to . In the light of the above statements, choose the correct answer from the options given below:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2Statement I is true but Statement II is false
Approach:
Check if relation R satisfies reflexive, symmetric, and transitive properties for equivalence. Analyze the set S for Statement II.
Step 1:Check reflexive property: (a, b)R(a, b)?
Step 2:Check symmetric property: (a₁, b₁)R(a₂, b₂) → (a₂, b₂)R(a₁, b₁)?
Step 3:Check transitive property
and : and
Step 4:Conclude Statement I
R is reflexive, symmetric, and transitive
Step 5:Analyze Statement II: Find set S
Step 6:Identify the geometric nature of S
is a horizontal line
Step 7:Compare with line y = x
Line has slope . Horizontal line has slope .
Step 8:Conclude Statement II
S represents a horizontal line, NOT parallel to
Final answer: [object Object]
Q4Single correctIntegral Calculus
Let , where C is the constant of integration. If , , then equals:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2
Approach:
Use integration by parts repeatedly to find g(x), then compute g(π/2) and g'(π/2).
Step 1:First integration by parts: u = x³, dv = sin(x)dx
Step 2:Second integration by parts: u = x², dv = cos(x)dx
Step 3:Third integration by parts: u = x, dv = sin(x)dx
Step 4:Combine all parts
Step 5:Evaluate g(π/2) using cos(π/2)=0, sin(π/2)=1
Step 6:Find g'(x) - since g(x) = ∫x³sin(x)dx
Step 7:Evaluate g'(π/2)
Step 8:Calculate 8(g(π/2) + g'(π/2))
Step 9:Express in standard form and identify coefficients
Step 10:Calculate α + β - γ
Final answer: [object Object]
Q5Single correctCo-ordinate Geometry
A rod of length eight units moves such that its ends A and B always lie on the lines and , respectively. If the locus of the point P, that divides the rod AB internally in the ratio is , then is equal to:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3
Approach:
Express point P in terms of parameters, use constraint |AB|=8, and derive the locus equation.
Step 1:Parametrize point A on line x - y + 2 = 0
Let where ✓
Step 2:Parametrize point B on line y + 2 = 0
Let where ✓
Step 3:Apply constraint |AB| = 8
Step 4:Find P dividing AB in ratio 2:1
Step 5:Express a in terms of y
Step 6:Express b in terms of x and y
Step 7:Calculate (b - a) in terms of x, y
Step 8:Calculate (a + 4)
Step 9:Substitute into constraint equation
Step 10:Multiply by 4 and expand
Step 11:Expand first square
Step 12:Expand second square
Step 13:Add and simplify
Step 14:Factor out 9 from appropriate terms
Step 15:Compare coefficients with 9(x² + αy² + βxy + γx + 28y) - 76 = 0
Step 16:Calculate α - β - γ
Final answer: [object Object]
Q6Single correctThree Dimensional Geometry
If the square of the shortest distance between the lines and is , where m, n are coprime numbers, then is equal to:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2
Approach:
Use formula for shortest distance between skew lines using cross product of direction vectors.
Step 1:Identify points and direction vectors for both lines
: Point , direction . : Point , direction
Step 2:Calculate P₂ - P₁
Step 3:Calculate d₁ × d₂ using determinant
Step 4:Expand determinant
Step 5:Calculate |d₁ × d₂|
Step 6:Calculate dot product (P₂ - P₁) · (d₁ × d₂)
Step 7:Calculate shortest distance
Step 8:Calculate d²
where
Step 9:Calculate m + n
Final answer: [object Object]
Q7Single correctLimit, Continuity and Differentiability
is equal to:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3
Approach:
Recognize this as a indeterminate form, separate into polynomial and exponential parts, then evaluate each independently
Step 1:Rewrite the expression by simplifying the radical:
Step 2:Combine the exponential terms into a single base with exponent
Step 3:Evaluate Part A: The polynomial fraction as
Step 4:Evaluate Part B: Recognize and exponent , giving form
Step 5:Simplify the expression inside the exponent
Step 6:Compute the limit in the exponent
Step 7:Part B evaluates to
Step 8:Multiply Part A and Part B for final answer
Final answer: [object Object]
Q8Single correctVector Algebra
Let the point A divide the line segment joining the points and internally in the ratio . If O is the origin and , then the value of r is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 4
Approach:
Use section formula to find A, then compute dot and cross products as given in the equation.
Step 1:Find coordinates of A using section formula
Step 2:Calculate OQ · OA
Step 3:Set up cross product OP × OA with a = (5r-1)/(r+1), b = (10r+2)/(r+1)
Step 4:Simplify b + 2a
Step 5:Calculate |OP × OA|²
Step 6:Substitute into given equation
Step 7:Multiply by (r+1)²
Step 8:Expand left side
Step 9:Expand right side
Step 10:Equate and solve
Step 11:Find r
or . Since ,
Final answer: [object Object]
Q9Single correctCo-ordinate Geometry
The length of the chord of the ellipse , whose mid-point is , is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3
Approach:
Use chord of ellipse with given midpoint formula, then find chord length.
Step 1:Identify ellipse parameters and midpoint
Ellipse: , so . Midpoint:
Step 2:Write chord equation using midpoint formula
Step 3:Simplify chord equation
or
Step 4:Substitute y into ellipse equation
Step 5:Expand and simplify
Step 6:Form quadratic equation
Step 7:Find x₁ - x₂ using quadratic formula
Step 8:Since y = 3/2 - x, find y₁ - y₂
Step 9:Calculate chord length
Final answer: [object Object]
Q10Single correctMatrices and Determinants
The system of equations , has no solution if
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3
Approach:
Use Gaussian elimination to find conditions for no solution (inconsistent system).
Step 1:Write augmented matrix
Step 2:Row operation: R₂ - R₁
:
Step 3:Row operation: R₃ - R₁
:
Step 4:Updated matrix
Step 5:Row operation: R₃ - 4R₂
:
Step 6:Analyze conditions for no solution
For no solution: coefficient = 0 but constant e 0. So and
Final answer: [object Object]
Q11Single correctTrigonometry
Let the range of the function be . Then the distance of the point from the line is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1
Approach:
Simplify the trigonometric product using identities, find range, then calculate distance from point to line.
Step 1:Apply the triple product identity for cosines
Step 2:Substitute into f(x)
Step 3:Apply double angle: 2cos(3x)sin(3x) = sin(6x)
Step 4:Apply double angle again: 2sin(6x)cos(6x) = sin(12x)
Step 5:Find range of f(x)
Since , we have
Step 6:Calculate distance from (5, 7) to line 3x + 4y + 12 = 0
Final answer: [object Object]
Q12Single correctDifferential Equations
Let be the solution of the differential equation and . Then is equal to:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 4
Approach:
Substitute u = x/y to transform into separable equation, integrate, and apply initial condition.
Step 1:Let u = x/y, so x = uy and dx/dy = u + y(du/dy)
Substituting:
Step 2:Simplify the equation
Step 3:Separate variables
Step 4:Integrate both sides
Step 5:Apply initial condition x(1) = π/2
Step 6:Find x(2) using y = 2
Step 7:Calculate cos(x(2)) using double angle formula
Let , so . Then .
Final answer: [object Object]
Q13Single correctLimit, Continuity and Differentiability
A spherical chocolate ball has a layer of ice-cream of uniform thickness around it. When the thickness of the ice-cream layer is 1 cm, the ice-cream melts at the rate of 81 cm³/min and the thickness of the ice-cream layer decreases at the rate of cm/min. The surface area (in cm²) of the chocolate ball (without the ice-cream layer) is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2
Approach:
Use related rates with the volume formula for spherical shell.
Step 1:Define variables: r = chocolate radius, t = ice cream thickness
Total radius . Volume of ice cream
Step 2:Find dV/dt by differentiating (r is constant)
Step 3:Substitute given values: t = 1, dV/dt = -81, dt/dt = -1/(4π)
Step 4:Solve for r
cm
Step 5:Calculate surface area of chocolate ball
cm²
Final answer: [object Object]
Q14Single correctComplex Numbers and Quadratic Equations
The number of complex numbers z, satisfying and , is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2
Approach:
Express z in exponential form, simplify the given condition to find θ values.
Step 1:Express z using |z| = 1
, so
Step 2:Calculate z/z̄ and z̄/z
,
Step 3:Add the two expressions
Step 4:Apply the given condition
Step 5:Find solutions for cos(2θ) = 1/2
in
Step 6:Find solutions for cos(2θ) = -1/2
in
Step 7:Count total solutions in [0, 2π)
Total distinct values of :
Final answer: [object Object]
Q15Single correctMatrices and Determinants
Let be matrix such that , and , then equals:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 1
Approach:
Use the three matrix equations to find the elements of matrix A, specifically a₂₃.
Step 1:From first equation A[0,1,0]ᵀ = [0,0,1]ᵀ, identify second column
Second column of A = , so
Step 2:From second equation A[4,1,3]ᵀ = [1,1,0]ᵀ, write row 2 equation
Step 3:From third equation A[2,1,2]ᵀ = [1,0,0]ᵀ, write row 2 equation
Step 4:From equation (ii), express a₂₁ in terms of a₂₃
Step 5:Substitute into equation (i)
Final answer: [object Object]
Q16Single correctIntegral Calculus
If , then equals:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 3
Approach:
Use property of definite integrals: ∫₀^(π/2) f(x)dx = ∫₀^(π/2) f(π/2-x)dx
Step 1:Find I using King's property
. Also
Step 2:Add the two expressions
Step 3:Apply King's property to main integral
Let , then
Step 4:Add and simplify
Step 5:Substitute u = cos 2x, simplify denominator
. Let ,
Step 6:Evaluate integral
Final answer: [object Object]
Q17Single correctStatistics and Probability
A board has 16 squares as shown in the figure: Out of these 16 squares, two squares are chosen at random. The probability that they have no side in common is :

(A)
(B)
(C)
(D)
SolutionAnswer: Option 2
Approach:
Count total ways to choose 2 squares and subtract adjacent pairs.
Step 1:Count total ways to choose 2 squares from 16
Step 2:Count horizontally adjacent pairs (4 rows × 3 pairs each)
Horizontal adjacencies:
Step 3:Count vertically adjacent pairs (4 columns × 3 pairs each)
Vertical adjacencies:
Step 4:Total adjacent pairs
Total adjacent =
Step 5:Calculate probability of no common side
Final answer: [object Object]
Q18Single correctCo-ordinate Geometry
Let the shortest distance from (a, 0), a > 0, to the parabola = 4x be 4. Then the equation of the circle passing through the point (a, 0) and the focus of the parabola, and having its centre on the axis of the parabola is :
(A)
(B)
(C)
(D)
SolutionAnswer: Option 2 - 6x + 5 = 0
Approach:
Find point (a,0) using shortest distance condition, then find circle through (a,0) and focus.
Step 1:Find foot of perpendicular from (a,0) to parabola y² = 4x
Point on parabola: . For perpendicular: (when )
Step 2:Calculate distance when foot is at (a-2, 2√(a-2))
Distance
Step 3:Set distance = 4 and solve for a
Step 4:Circle passes through (5,0) and focus (1,0), center on x-axis
Center at midpoint: . Radius =
Step 5:Write circle equation
Final answer: [object Object]
Q19Single correctBinomial Theorem and its Simple Applications
If in the expansion of , the coefficients of x and are 1 and -2, respectively, then is equal to :
(A)
(B)
(C)
(D)
SolutionAnswer: Option 213
Approach:
Expand up to x² term and match coefficients.
Step 1:Expand each factor to x² terms
,
Step 2:Multiply and collect x coefficient
Coefficient of : ... (i)
Step 3:Collect x² coefficient
Coefficient of :
Step 4:Simplify x² coefficient equation
Step 5:Solve system: p - q = 1, p + q = 5
,
Step 6:Calculate p² + q²
Final answer: [object Object]
Q20Single correctIntegral Calculus
If the area of the region is , then the value of a is:
(A)
(B)
(C)
(D)
SolutionAnswer: Option 35
Approach:
Set up and evaluate the double integral for the area, then solve for a.
Step 1:Split integral using |x| definition
Step 2:Simplify first integral (x < 0, |x| = -x)
Step 3:Evaluate second integral
Step 4:Total area
Step 5:Set equal to given area and solve
Final answer: [object Object]
Q21NumericalStatistics and Probability
The variance of the numbers
SolutionAnswer: 8788
Approach:
Use variance formula for arithmetic progression.
Step 1:Identify AP parameters
First term , common difference
Step 2:Find number of terms using last term = 320
Step 3:Apply variance formula for AP
Step 4:Calculate final value
Final answer: [object Object]
Q22NumericalSequence and Series
The roots of the quadratic equation - px + q = 0 are and terms of an arithmetic progression with common difference . If the sum of the first 11 terms of this arithmetic progression is 88, then q - 2p is equal to
SolutionAnswer: 474
Approach:
Use AP formulas to find the roots, then apply Vieta's formulas.
Step 1:Set up AP with common difference d = 3/2
Let first term be a. Then ,
Step 2:Use sum condition: S₁₁ = 88
Step 3:Find the roots (10th and 11th terms)
,
Step 4:Apply Vieta's formulas to 3x² - px + q = 0
Sum: . Product:
Step 5:Calculate q - 2p
Final answer: [object Object]
Q23NumericalPermutations and Combinations
The number of ways 5 boys and 4 girls can sit in a row so that either all the boys sit together or no two boys sit together, is
SolutionAnswer: 17280
Approach:
Use complementary cases: (1) all boys together, (2) no two boys together.
Step 1:Case 1: All 5 boys sit together
Treat boys as single unit. Total units = 1 (boys block) + 4 (girls) = 5
Step 2:Count arrangements for Case 1
5 units can be arranged in ways. Boys within block: ways. Total =
Step 3:Case 2: No two boys sit together
First arrange 4 girls in a row: ways. This creates 5 gaps:
Step 4:Place boys in gaps
5 boys in 5 gaps: ways. Total =
Step 5:Total arrangements
Total =
Final answer: [object Object]
Q24NumericalCo-ordinate Geometry
The focus of the parabola is the centre of the circle C of radius 5. If the values of , for which C passes through the point of intersection of the lines and , are and , , then is equal to
SolutionAnswer: 15
Approach:
Find focus of parabola (circle center), find line intersection point, use circle equation.
Step 1:Find focus of parabola y² = 4x + 16 = 4(x + 4)
Vertex at , . Focus at
Step 2:Find intersection of lines 3x - y = 0 and x + λy = 4
From : ,
Step 3:Apply circle equation (x+3)² + y² = 25
Step 4:Simplify and form quadratic
Step 5:Solve quadratic
Step 6:Calculate 12λ₁ + 29λ₂
Final answer: [object Object]
Q25NumericalComplex Numbers and Quadratic Equations
Let be the roots of the equation with . Let . If , , and , then is equal to
SolutionAnswer: 31
Approach:
Use recurrence relation for Pₙ = αⁿ - βⁿ and given values to find α⁴ + β⁴.
Step 1:Use recurrence relation Pₙ = aPₙ₋₁ + bPₙ₋₂
:
Step 2:Use another recurrence equation
:
Step 3:Solve system for a and b
From (i): . From (ii): . Solving:
Step 4:Find α + β and αβ
For : ,
Step 5:Calculate |α⁴ + β⁴|
Final answer: [object Object]
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