META DESCRIPTIONWBCHSE Class XII Semester III Model Question Bank Part 33 includes advanced Physics and Chemistry numericals, Biology case studies, Mathematics mastery problems, English writing, Bengali analytical practice, score improvement, error analysis and final examination strategy.SEO KEYWORDSWBCHSE Class 12 Semester IIIWBCHSE Part 33WBCHSE model question bankClass 12 final preparationWBCHSE advanced practiceWBCHSE Physics questionsWBCHSE Chemistry questionsWBCHSE Biology case studyWBCHSE Mathematics challengeWBCHSE English writingWBCHSE Bengali preparationWBCHSE HOTSWBCHSE competency questionsClass 12 mock testWBCHSE score improvementClass 12 error analysisWBCHSE final revisionHASHTAGS#WBCHSE#Class12#SemesterIII#ModelQuestionBank#FinalMastery#Physics#Chemistry#BiologicalScience#Mathematics#English#Bengali#HOTS#CompetencyBasedLearning#CaseStudy#NumericalPractice#MockTest#ScoreImprovement#FinalRevision#ExamPreparation#StudentSuccessPart 33 now adds a stronger score-improvement layer: not just solving more questions, but tracking whether accuracy, speed, presentation, and confidence are actually improving.

October 04, 2026

Writing

WBCHSE CLASS XII SEMESTER III

Subject-Wise Model Question Bank — Part 33

FINAL MASTERY & SCORE-IMPROVEMENT SERIES

Advanced Practice • Mixed Competency • Multi-Step Numericals • Case Studies • HOTS • Assertion–Reason • Data Interpretation • Literature Mastery • Bengali Analytical Writing • Rapid Revision • Score Improvement

INTRODUCTION

The preparation journey has now reached an important stage.

At this level, repeatedly reading the same material is not enough.

The student should now ask:

Can I retrieve the concept without looking at the book?

Then:

Can I apply it to a question I have never seen before?

And finally:

Can I present the answer clearly within the available time?

Part 33 is designed around these three abilities:

KNOW

Understand the concept.

APPLY

Use the concept in a new situation.

PRESENT

Communicate the answer accurately.

This part also introduces a Score Improvement System.

HOW TO USE THIS PART

For each subject:

Attempt the questions independently.

Give yourself a time limit.

Mark doubtful questions.

Check answers only after completing the section.

Record mistakes.

Reattempt difficult questions after 24–48 hours.

PART A — PHYSICS

PHYSICS FINAL MASTERY CHALLENGE

CASE STUDY — CAPACITOR AND ENERGY

A capacitor of capacitance 8\mu F is charged to 50V.

Q1.

Calculate the charge stored.

Q2.

Calculate the energy stored.

Q3.

If the potential difference is reduced to half, what happens to the stored energy?

Q4.

If capacitance is doubled while voltage remains unchanged, what happens to stored energy?

CURRENT ELECTRICITY

A 12\Omega resistor is connected across a 24V source.

Q5.

Calculate the current.

Q6.

Calculate the power dissipated.

Q7.

Calculate the energy dissipated in 2 minutes.

Q8.

If the resistance becomes 24\Omega while voltage remains 24V, calculate the new current.

MAGNETISM AND ELECTROMAGNETIC INDUCTION

Q9.

A 0.5m wire carries 4A current perpendicular to a 0.25T magnetic field. Find the force.

Q10.

A 100-turn coil experiences a flux change of 0.05Wb in 0.25s. Find average induced emf.

Q11.

What happens to induced emf if the number of turns is tripled?

Q12.

State the physical meaning of Lenz's law.

ASSERTION–REASON

Q13.

Assertion: The energy stored in a capacitor is proportional to the square of the potential difference when capacitance is constant.

Reason:

[ U=\frac12CV^2 ]

Q14.

Assertion: The magnetic force on a charged particle is zero when the particle moves parallel to the magnetic field.

Reason:

[ F=qvB\sin\theta ]

and \theta=0^\circ.

PHYSICS HOTS

Q15.

Why does increasing the plate area increase the capacitance?

Q16.

Why does the magnetic force change the direction of a charged particle's velocity rather than its speed when the force remains perpendicular to velocity?

Q17.

Why does increasing the rate of change of magnetic flux increase induced emf?

PHYSICS ANSWERS

Q1.

[ Q=CV ]

[ =8\times10^{-6}\times50 ]

[ =4\times10^{-4}C ]

Q2.

[ U=\frac12CV^2 ]

[ =\frac12(8\times10^{-6})(50)^2 ]

[ =0.01J ]

Q3.

Since:

[ U\propto V^2 ]

halving V makes the energy one-fourth.

Q4.

Energy doubles because:

[ U=\frac12CV^2 ]

Q5.

[ I=\frac{24}{12}=2A ]

Q6.

[ P=VI=24\times2=48W ]

Q7.

[ t=120s ]

[ E=Pt=48\times120=5760J ]

Q8.

[ I=\frac{24}{24}=1A ]

Q9.

[ F=BIL ]

[ =0.25\times4\times0.5 ]

[ =0.5N ]

Q10.

[ \varepsilon=N\frac{\Delta\Phi}{\Delta t} ]

[ =100\times\frac{0.05}{0.25} ]

[ =20V ]

Q11.

It becomes three times larger, if all other conditions remain unchanged.

Q12.

The induced effect opposes the change in magnetic flux that produces it.

Q13.

Both Assertion and Reason are correct, and the Reason explains the Assertion.

Q14.

Both Assertion and Reason are correct, and the Reason explains the Assertion.

Q15.

For an ideal parallel-plate capacitor, capacitance is proportional to plate area.

Q16.

A perpendicular force changes direction of velocity without doing work on the particle.

Q17.

Faraday's law gives:

[ |\varepsilon|=N\left|\frac{d\Phi}{dt}\right| ]

so faster flux change produces greater emf.

PART B — CHEMISTRY

CHEMISTRY FINAL MASTERY CHALLENGE

ELECTROCHEMISTRY

A cell has:

[ E^\circ_{cathode}=0.72V ]

and

[ E^\circ_{anode}=0.28V ]

Q1.

Calculate E^\circ_{cell}.

Q2.

Is the standard cell reaction thermodynamically favourable?

Q3.

What is the sign of \Delta G^\circ?

Q4.

Write the relationship between E^\circ_{cell} and \Delta G^\circ.

CHEMICAL KINETICS

A first-order reaction has:

[ k=0.099,min^{-1} ]

Q5.

Calculate its half-life.

Q6.

What happens to half-life if k increases?

Q7.

Why does temperature generally increase reaction rate?

Q8.

What is activation energy?

COORDINATION CHEMISTRY

Q9.

Define coordination compound.

Q10.

Define ligand.

Q11.

What is a monodentate ligand?

Q12.

What is a bidentate ligand?

Q13.

What is coordination number?

Q14.

Why may coordination compounds be coloured?

CHEMISTRY HOTS

Q15.

Why does a catalyst not alter the equilibrium constant?

Q16.

Why does a positive standard cell potential correspond to a negative standard Gibbs energy change?

Q17.

Why can molar conductivity increase on dilution?

CHEMISTRY ANSWERS

Q1.

[ E^\circ_{cell}=0.72-0.28=0.44V ]

Q2.

Yes, under standard conditions the positive cell potential indicates a favourable spontaneous cell reaction.

Q3.

Negative.

Q4.

[ \Delta G^\circ=-nFE^\circ_{cell} ]

Q5.

[ t_{1/2}=\frac{0.693}{0.099} ]

[ =7min ]

Q6.

It decreases.

Q7.

A greater fraction of molecules can acquire energy sufficient to overcome the activation barrier.

Q8.

Minimum energy barrier required for effective reaction.

Q9.

A compound containing a central metal atom/ion coordinated with ligands.

Q10.

An electron-pair donor attached to a central metal.

Q11.

A ligand with one donor atom.

Q12.

A ligand with two donor atoms.

Q13.

Number of donor atoms directly attached to the central metal.

Q14.

Electronic transitions can involve absorption of visible light.

Q15.

The catalyst provides an alternative pathway for both forward and reverse reactions without changing the equilibrium constant.

Q16.

[ \Delta G^\circ=-nFE^\circ_{cell} ]

Since n, F, and E^\circ_{cell} are positive, \Delta G^\circ is negative.

Q17.

Dilution can increase ionisation and ionic mobility, increasing molar conductivity.

PART C — BIOLOGICAL SCIENCE

BIOLOGY FINAL MASTERY CHALLENGE

CASE STUDY — GENETIC INFORMATION

A DNA molecule contains information required for the synthesis of a functional protein.

Q1.

What is the basic unit of DNA?

Q2.

What is replication?

Q3.

Why is DNA replication semi-conservative?

Q4.

What is transcription?

Q5.

What is translation?

Q6.

What is the role of mRNA?

Q7.

What is a codon?

Q8.

How can a mutation affect gene expression or protein function?

EVOLUTION CASE STUDY

A population contains heritable variation. Environmental conditions favour individuals carrying a particular characteristic.

Q9.

Define heritable variation.

Q10.

What is natural selection?

Q11.

Why is inheritance necessary for natural selection to produce evolutionary change?

Q12.

What may happen to an advantageous characteristic over generations?

Q13.

Why is an advantageous characteristic not necessarily advantageous in every environment?

BIOLOGY HOTS

Q14.

Why is mutation not always harmful?

Q15.

Why are homologous structures important in evolutionary studies?

Q16.

Why is fossil evidence valuable?

Q17.

Why is biodiversity important?

DIAGRAM CHALLENGE

Q18.

Draw and label a nucleotide.

Q19.

Draw and label DNA double helix.

Q20.

Draw a replication fork.

Q21.

Draw a basic transcription unit.

Q22.

Draw and label a chromosome.

BIOLOGY ANSWERS

Nucleotide.

Copying of DNA.

Each daughter DNA contains one parental strand and one newly synthesised strand.

Formation of RNA using DNA as a template.

Protein/polypeptide synthesis using mRNA information.

It carries information for protein synthesis.

Three-nucleotide sequence on mRNA.

It may alter a DNA sequence and therefore potentially alter RNA or protein production.

Variation that can be transmitted genetically.

Differential survival and reproduction associated with heritable variation.

Without inheritance, the advantageous characteristic would not reliably pass to descendants.

Its frequency may increase.

Advantage depends on environmental conditions.

Effects may be harmful, neutral or beneficial.

Shared structural patterns can indicate common ancestry.

It provides evidence about past life and evolutionary history.

It supports ecosystem functioning and resilience.

PART D — MATHEMATICS

FINAL 40-PROBLEM MASTERY CHALLENGE

CALCULUS

Q1.

Differentiate:

[ y=x^4+3x^2-5x ]

Q2.

Differentiate:

[ y=x^2\cos x ]

Q3.

Find:

[ \int(4x^3+6x),dx ]

Q4.

Evaluate:

[ \int_0^2 2x,dx ]

Q5.

Find:

[ \frac{d}{dx}(e^x\sin x) ]

Q6.

Find the stationary point of:

[ y=x^2-6x+8 ]

Q7.

Find:

[ \frac{d}{dx}\ln x ]

Q8.

Evaluate:

[ \int \frac1x dx ]

DIFFERENTIAL EQUATIONS

Q9.

Solve:

[ \frac{dy}{dx}=4x^3+2x ]

Q10.

Find the order:

[ \frac{d^4y}{dx^4}+y=0 ]

Q11.

Find the degree:

[ \left(\frac{d^3y}{dx^3}\right)^2+y=0 ]

Q12.

Solve:

[ \frac{dy}{dx}=5 ]

VECTORS

Q13.

Find the magnitude:

[ 5\hat i+12\hat j ]

Q14.

Find:

[ (3\hat i+2\hat j)\cdot(2\hat i-\hat j) ]

Q15.

When is the dot product zero?

Q16.

When is the cross product zero?

Q17.

When is cross-product magnitude maximum?

Q18.

Define a unit vector.

PROBABILITY

Q19.

A fair die is thrown once. Find the probability of obtaining a number less than 5.

Q20.

Find the probability of obtaining a multiple of 2.

Q21.

Two fair coins are tossed. Find the probability of getting exactly one tail.

Q22.

If:

[ P(A)=0.6 ]

find P(A').

Q23.

What is the probability of a certain event?

Q24.

What is the probability of an impossible event?

THREE-DIMENSIONAL GEOMETRY

Q25.

Write the equation of the xy-plane.

Q26.

Write the equation of the yz-plane.

Q27.

Write the equation of the xz-plane.

Q28.

Write the general point on the y-axis.

Q29.

State the condition for direction cosines.

Q30.

Find the distance between:

[ (1,2,3) ]

and

[ (5,2,3) ]

MIXED CHALLENGE

Q31.

If f(x)=x^2+3x, find f'(2).

Q32.

Evaluate:

[ \int 4e^x dx ]

Q33.

What is the angle between two non-zero perpendicular vectors?

Q34.

What is the cross product of parallel vectors?

Q35.

If P(A)=0.25, find P(A').

Q36.

Define mutually exclusive events.

Q37.

Find the magnitude of:

[ 7\hat k ]

Q38.

Find:

[ \hat i\cdot\hat i ]

Q39.

Find:

[ \hat j\times\hat j ]

Q40.

What can a zero derivative indicate?

MATHEMATICS ANSWERS

[ 4x^3+6x-5 ]

[ 2x\cos x-x^2\sin x ]

[ x^4+3x^2+C ]

[ 4 ]

[ e^x\sin x+e^x\cos x ]

[ x=3,\quad y=-1 ]

[ \frac1x ]

[ \ln|x|+C ]

[ y=x^4+x^2+C ]

[ y=5x+C ]

[ 6-2=4 ]

For perpendicular vectors.

For parallel or anti-parallel vectors.

When vectors are perpendicular.

A vector having magnitude 1.

[ \frac46=\frac23 ]

[ \frac36=\frac12 ]

[ \frac12 ]

[ 0.4 ]

[ z=0 ]

[ x=0 ]

[ y=0 ]

[ (0,y,0) ]

[ l^2+m^2+n^2=1 ]

[ 4 ]

[ f'(x)=2x+3 ]

Therefore:

[ f'(2)=7 ]

[ 4e^x+C ]

90^\circ

Zero vector.

0.75

Events that cannot occur simultaneously.

Zero vector.

A stationary point may occur.

PART E — ENGLISH

FINAL WRITING MASTERY TEST

READING

Read carefully:

Examination preparation becomes more effective when students understand their own learning patterns. Some students remember better through repeated recall, while others benefit from diagrams, written practice or discussion. The important point is not to copy someone else's method blindly but to discover which methods improve one's own understanding and retention. Self-evaluation therefore becomes an essential part of serious preparation.

QUESTIONS

Q1.

What makes examination preparation more effective?

Q2.

Do all students necessarily learn best in the same way?

Q3.

What methods may help students remember information?

Q4.

Why should students avoid blindly copying another person's method?

Q5.

Why is self-evaluation important?

Q6.

Give a suitable title.

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