MP Board Class 12 Physics Chapter 1: विद्युत आवेश एवं क्षेत्र — सम्पूर्ण हिंदी नोट्स 2027
अध्याय 1: विद्युत आवेश एवं क्षेत्र (Electric Charges and Fields) — यह MP Board कक्षा 12 भौतिकी का प्रथम अध्याय है और परीक्षा की दृष्टि से अत्यंत महत्वपूर्ण है। इस अध्याय से प्रतिवर्ष 8-12 अंकों के प्रश्न पूछे जाते हैं। विद्युत आवेश की मूल अवधारणा, कूलॉम का नियम, विद्युत क्षेत्र, गाउस का नियम — ये सभी टॉपिक MP Board 2027 की परीक्षा के लिए आवश्यक हैं। यहाँ हम सम्पूर्ण हिंदी नोट्स प्रस्तुत कर रहे हैं।
विद्युत आवेश (Electric Charge) पदार्थ का एक मूलभूत गुण है, जिसके कारण विद्युत एवं चुंबकीय प्रभाव उत्पन्न होते हैं। यह एक अदिश राशि (Scalar Quantity) है।
🧪 आवेश के प्रकार
धन आवेश (Positive Charge): प्रोटॉन पर उपस्थित (+)
ऋण आवेश (Negative Charge): इलेक्ट्रॉन पर उपस्थित (−)
समान आवेश एक-दूसरे को प्रतिकर्षित करते हैं
असमान आवेश एक-दूसरे को आकर्षित करते हैं
📘 आवेश के मूल गुण
क्वांटीकरण: Q = ±ne, e = 1.6e-19 C
संरक्षण: आवेश न उत्पन्न होता है न नष्ट
योगात्मकता: कुल आवेश = बीजगणितीय योग
🔋 2. चालक, कुचालक एवं आवेशन की विधियाँ
गुण
चालक
कुचालक
आवेश प्रवाह
सरलता से
नहीं होता
उदाहरण
धातुएँ, मानव शरीर
रबर, काँच, प्लास्टिक
मुक्त इलेक्ट्रॉन
भरपूर
नहीं
🔄 आवेशन की विधियाँ
घर्षण: रगड़ने से आवेशन
संपर्क (Conduction): स्पर्श कराने पर
प्रेरण (Induction): बिना संपर्क के
📐 3. कूलॉम का नियम (Coulomb’s Law)
दो स्थिर बिंदु आवेशों के बीच विद्युत बल, आवेशों के गुणनफल के अनुक्रमानुपाती तथा दूरी के वर्ग के व्युत्क्रमानुपाती होता है।
📘 सूत्र: F = k x q1 x q2 / r2
k = 9e9 Nm2/C2, e0 = 8.854e-12 C2/Nm2
माध्यम में: Fm = F/er
🌐 4. विद्युत क्षेत्र एवं विद्युत बल रेखाएँ
विद्युत क्षेत्र: आवेश के चारों ओर वह क्षेत्र जिसमें कोई अन्य आवेश बल अनुभव करे। E = F/q0 = kq/r2
〰️ बल रेखाओं के गुण
धन से निकल ऋण पर समाप्त
कभी एक-दूसरे को नहीं काटतीं
घनत्व = क्षेत्र की प्रबलता
🧲 5. विद्युत द्विध्रुव (Electric Dipole)
समान परिमाण के दो विपरीत आवेशों (+q और -q) का निकाय जो दूरी 2a से पृथक हों।
📘 सूत्र:
द्विध्रुव आघूर्ण: p = q x 2a
अक्षीय क्षेत्र: Ea = 2k x p / r3
निरक्षीय क्षेत्र: Ee = k x p / r3
बलाघूर्ण: t = pE sinθ
🔮 6. गाउस का नियम (Gauss’s Law)
किसी बंद पृष्ठ से गुज़रने वाला कुल विद्युत फ्लक्स, पृष्ठ द्वारा परिबद्ध कुल आवेश का 1/e0 गुना होता है।
📘 सूत्र: o E.dS = Qin / e0
अनुप्रयोग
स्थिति
क्षेत्र सूत्र
अनंत तार
E = l/(2pe0r)
अनंत चादर
E = s/(2e0)
गोलीय कोश (बाहर)
E = Q/(4pe0r2)
गोलीय कोश (अंदर)
E = 0
📝 7. महत्वपूर्ण सूत्र
क्र.
राशि
सूत्र
1
कूलॉम बल
F = kq1q2/r2
2
विद्युत क्षेत्र
E = F/q0 = kq/r2
3
विद्युत फ्लक्स
F = E.A.cosθ
4
द्विध्रुव आघूर्ण
p = q x 2a
5
बलाघूर्ण
t = pE sinθ
6
गाउस नियम
o E.dS = Q/e0
🎯 MP Board Exam Tip 2027: द्विध्रुव के अक्षीय/निरक्षीय क्षेत्र सूत्र, गाउस नियम के अनुप्रयोग और कूलॉम बल के Numerical — ये टॉपिक MP Board में सर्वाधिक पूछे जाते हैं।
❓ अक्सर पूछे जाने वाले प्रश्न
प्रश्न 1: विद्युत आवेश क्या है? इसकी SI इकाई?
उत्तर: विद्युत आवेश पदार्थ का मूलभूत गुण है जिससे विद्युतचुंबकीय प्रभाव उत्पन्न होते हैं। SI इकाई कूलॉम (C) है।
प्रश्न 2: कूलॉम का नियम लिखिए।
उत्तर: दो स्थिर बिंदु आवेशों के बीच बल आवेशों के गुणनफल के अनुक्रमानुपाती तथा दूरी के वर्ग के व्युत्क्रमानुपाती होता है। F = kq1q2/r2
प्रश्न 3: आवेश के क्वांटीकरण से क्या अभिप्राय है?
उत्तर: आवेश सदैव e = 1.6e-19 C के पूर्ण गुणजों में पाया जाता है। Q = ±ne
प्रश्न 4: विद्युत बल रेखाओं की तीन विशेषताएँ?
उत्तर: धन से निकल ऋण पर समाप्त, कभी नहीं काटतीं, घनत्व क्षेत्र की प्रबलता दर्शाता है।
प्रश्न 5: गाउस का नियम लिखिए।
उत्तर: बंद पृष्ठ से कुल फ्लक्स = Qin/e0। E = l/(2pe0r) अनंत तार के लिए।
प्रश्न 6: द्विध्रुव आघूर्ण की परिभाषा?
उत्तर: p = q x 2a, SI इकाई C-m
प्रश्न 7: प्रेरण द्वारा आवेशन क्या है?
उत्तर: बिना संपर्क के आवेशन। आवेशित वस्तु को पास लाने पर अनावेशित में आवेश पृथक्करण।
प्रश्न 8: चालक और कुचालक में अंतर?
उत्तर: चालकों में मुक्त इलेक्ट्रॉन होते हैं (धातुएँ)। कुचालकों में नहीं (रबर, काँच)।
Class 12 Physics Imp Qs 2027 — Chapter-wise VSA, SA &…
MP Board Class 12 Physics Important Questions 2027 — Physics carries 70 marks in the MP Board Class 12 exams and is divided into 9 chapters covering Electrostatics, Current Electricity, Magnetism, Electromagnetic Induction, EM Waves, Optics, Dual Nature, Atoms & Nuclei, and Semiconductor Devices. This compilation features chapter-wise important questions across Very Short Answer (1 mark), Short Answer (2-3 marks), and Long Answer (4-5 marks) categories — designed to help you target high-weightage topics and score 90%+ in the 2027 board exams.
Q1. Define electric potential at a point. Write its SI unit.
Q2. What is the dielectric constant of a conductor?
Q3. Write the relation between electric field and potential gradient.
Q4. What is the net capacitance when two capacitors are connected in series?
Short Answer Questions (2-3 Marks)
Q5. Derive the expression for potential due to a point charge at a distance r.
Q6. Explain the effect of inserting a dielectric slab on the capacitance of a parallel plate capacitor.
Q7. Two capacitors of 4 µF and 6 µF are connected in series across a 12 V battery. Find the charge on each capacitor.
Q8. Define equipotential surface. Draw the equipotential surfaces for a point charge.
Long Answer Questions (4-5 Marks)
Q9. Derive the expression for the capacitance of a parallel plate capacitor with a dielectric medium between the plates.
Q10. Derive an expression for the energy stored in a charged capacitor. What is the energy density?
Q11. State and explain the principle of a Van de Graaff generator. Draw a labelled diagram.
📘 Key Formula: Capacitance of Parallel Plate Capacitor
C = ε₀εᵣA / d where ε₀ = permittivity of free space, εᵣ = dielectric constant, A = plate area, d = separation
⚡ Chapter 2: Current Electricity
Very Short Answer Questions (1 Mark)
Q1. State Ohm’s law. Write the condition for its validity.
Q2. Define resistivity. Write its SI unit.
Q3. What is the drift velocity of electrons in a conductor?
Q4. Write the colour code of a carbon resistor with bands: Yellow, Violet, Orange, Gold.
Short Answer Questions (2-3 Marks)
Q5. Derive the relation between current and drift velocity: I = neAvd.
Q6. Explain how resistivity varies with temperature for conductors and semiconductors.
Q7. A wire of resistance R is stretched to double its length. Find the new resistance.
Q8. State and explain Kirchhoff’s laws with suitable diagrams.
Long Answer Questions (4-5 Marks)
Q9. Derive the principle of a Wheatstone bridge and obtain the condition for a balanced bridge. State its applications.
Q10. Derive an expression for the equivalent emf and internal resistance of two cells connected in series and parallel.
Q11. Using Kirchhoff’s laws, obtain the current in each branch of a given network of resistors.
⚡ Chapter 3: Moving Charges & Magnetism
Very Short Answer Questions (1 Mark)
Q1. What is the Lorentz force? Write its expression.
Q2. Define the SI unit of magnetic field (Tesla).
Q3. What is the cyclotron frequency? Write its formula.
Q4. State the right-hand thumb rule for magnetic field direction.
Short Answer Questions (2-3 Marks)
Q5. Derive the expression for the force on a current-carrying conductor placed in a magnetic field.
Q6. Derive Biot-Savart’s law and apply it to find the magnetic field at the centre of a circular current loop.
Q7. Two parallel current-carrying conductors attract each other when currents are in the same direction. Explain.
Q8. Explain the working of a cyclotron with a labelled diagram.
Long Answer Questions (4-5 Marks)
Q9. State Ampere’s circuital law. Use it to derive the magnetic field due to an infinitely long straight current-carrying conductor.
Q10. Derive the expression for the torque on a current loop placed in a uniform magnetic field. Explain the working of a moving coil galvanometer.
⚡ Chapter 4: Electromagnetic Induction & Alternating Current
Very Short Answer Questions (1 Mark)
Q1. State Faraday’s law of electromagnetic induction.
Q2. What is Lenz’s law? How does it conserve energy?
Q3. Define self-inductance. Write its SI unit.
Q4. What is the phase difference between voltage and current in a purely inductive AC circuit?
Short Answer Questions (2-3 Marks)
Q5. Derive the expression for the induced emf in a coil rotating in a uniform magnetic field (AC generator principle).
Q6. Explain the construction and working of a step-up transformer. Derive the turns ratio relation.
Q7. A 100 mH inductor is connected to a 50 Hz AC source of 200 V. Find the inductive reactance and rms current.
Q8. Define the Q-factor of a series LCR circuit. Explain its significance.
Long Answer Questions (4-5 Marks)
Q9. Derive the expression for the impedance and resonant frequency of a series LCR circuit. Draw the resonance curve.
Q10. Explain the principle, construction, and working of an AC generator (alternator). Draw the output waveform.
🎯 Exam Tip: MP Board frequently asks numerical problems from LCR circuits and transformers in the 4-5 mark section. Practice impedance calculation, resonance frequency, and turns ratio problems thoroughly.
⚡ Chapter 5: Electromagnetic Waves
Very Short Answer Questions (1 Mark)
Q1. Who predicted the existence of electromagnetic waves?
Q2. Write the speed of electromagnetic waves in vacuum.
Q3. What is the displacement current? Write its expression.
Q4. Name the electromagnetic wave used in radar systems.
Short Answer Questions (2-3 Marks)
Q5. Write Maxwell’s equations in integral form. Explain their physical significance.
Q6. List the different regions of the electromagnetic spectrum in order of increasing wavelength. Give one application of each.
Q7. Show that c = 1/√(μ₀ε₀) from Maxwell’s equations.
Q8. Explain how electromagnetic waves are produced by an oscillating charge.
Long Answer Questions (4-5 Marks)
Q9. Derive the wave equation for electromagnetic waves from Maxwell’s equations in free space. Show that EM waves are transverse in nature.
⚡ Chapter 6: Ray Optics & Optical Instruments
Very Short Answer Questions (1 Mark)
Q1. State the laws of reflection.
Q2. Define critical angle and total internal reflection.
Q3. What is the power of a lens? Write its SI unit.
Q4. Write the lens maker’s formula.
Short Answer Questions (2-3 Marks)
Q5. Derive the mirror formula 1/f = 1/v + 1/u for a concave mirror.
Q6. Derive the lens maker’s formula for a thin lens in air.
Q7. Explain the formation of a rainbow using total internal reflection and dispersion concepts.
Q8. A convex lens of focal length 15 cm forms a real image at 30 cm. Find the object distance.
Long Answer Questions (4-5 Marks)
Q9. Explain the construction and working of a compound microscope. Derive an expression for its magnifying power.
Q10. Explain the construction and working of an astronomical telescope. Derive the expression for its magnifying power in normal adjustment.
🎯 Exam Tip: MP Board 2027 — Ray diagram questions are very common in Optics. Practice drawing ray diagrams for microscopes, telescopes, and image formation by mirrors/lenses. Marks are often awarded for clean, labelled diagrams.
⚡ Chapter 7: Wave Optics
Very Short Answer Questions (1 Mark)
Q1. State Huygens’ principle.
Q2. Define coherence of light sources.
Q3. Write the condition for constructive and destructive interference.
Q4. What is the fringe width in Young’s double-slit experiment?
Short Answer Questions (2-3 Marks)
Q5. Derive the expression for fringe width in Young’s double-slit experiment.
Q6. Explain diffraction of light at a single slit and derive the condition for minima.
Q7. Distinguish between interference and diffraction patterns.
Q8. What is the polarisation of light? Explain Brewster’s law.
Long Answer Questions (4-5 Marks)
Q9. Describe Young’s double-slit experiment. Derive the expression for the intensity distribution of the interference pattern.
Q10. State Huygens’ principle. Using it, prove the laws of reflection and refraction.
⚡ Chapter 8: Dual Nature of Radiation & Matter
Very Short Answer Questions (1 Mark)
Q1. State Einstein’s photoelectric equation.
Q2. Define work function and threshold frequency.
Q3. Write de Broglie’s hypothesis. Give the expression for de Broglie wavelength.
Q4. What is the stopping potential in photoelectric effect?
Short Answer Questions (2-3 Marks)
Q5. Explain the experimental observations of the photoelectric effect that could not be explained by classical wave theory.
Q6. Derive an expression for de Broglie wavelength of an electron accelerated through a potential V.
Q7. The work function of a metal is 2.3 eV. Find the maximum kinetic energy of photoelectrons when light of wavelength 400 nm falls on it.
Q8. Distinguish between photoelectric effect and Compton effect.
Long Answer Questions (4-5 Marks)
Q9. Describe the experimental setup of the photoelectric effect. Explain how Einstein’s photoelectric equation explains the observations.
Q10. Explain Davisson-Germer experiment. How did it confirm de Broglie’s hypothesis?
⚡ Chapter 9: Semiconductor Electronics
Very Short Answer Questions (1 Mark)
Q1. Distinguish between intrinsic and extrinsic semiconductors.
Q2. What is a p-n junction? Draw the symbol of a diode.
Q3. Define the forbidden energy gap. How does it vary between conductors, semiconductors, and insulators?
Q4. Write the truth table of a NAND gate.
Short Answer Questions (2-3 Marks)
Q5. Explain the formation of the depletion region in a p-n junction. Draw the V-I characteristic of a diode.
Q6. Explain the working of a full-wave rectifier with a circuit diagram.
Q7. Distinguish between an LED and a solar cell in terms of construction and working.
Q8. Realise a NOR gate using NAND gates only.
Long Answer Questions (4-5 Marks)
Q9. Explain the working of a p-n junction diode as a half-wave rectifier. Derive the expression for ripple factor and efficiency.
Q10. Explain the construction and working of an n-p-n transistor as an amplifier in common emitter configuration. Derive the expression for voltage gain.
Logic Gate
Symbol
Boolean Expression
Truth Table (Y)
AND
D-shaped
Y = A · B
1 only when A=1, B=1
OR
Shield-shaped
Y = A + B
1 if any input is 1
NOT
Triangle + circle
Y = Ā
Inverts input
NAND
AND + circle
Y = (A · B)’
0 only when A=1, B=1
NOR
OR + circle
Y = (A+B)’
1 only when A=0, B=0
❓ FAQs — Physics Board Exam Strategy
Q1. Which chapters have the highest weightage in MP Board Class 12 Physics?
Electrostatic Potential & Capacitance, Current Electricity, Moving Charges & Magnetism, and Ray Optics typically carry the highest marks (8-10 marks each). Semiconductor Electronics and EM Waves are lighter (4-6 marks each) but easier to score.
Q2. How should I study numericals for the Physics exam?
Focus on: (a) capacitor combinations and energy, (b) Kirchhoff’s laws and Wheatstone bridge, (c) magnetic field due to current-carrying conductors, (d) LCR circuits and transformers, (e) lens formula and magnifying power. Practice all NCERT numerical examples — MP Board often repeats similar patterns.
Q3. Are derivations important for the MP Board Physics paper?
Yes — derivations typically account for 20-25 marks in the 4-5 mark section. Key derivations: mirror formula, lens maker’s formula, Wheatstone bridge, AC generator, compound microscope, photoelectric equation, transistor amplifier. Write each derivation step-by-step with clear labelling.
Q4. How many diagrams should I practice?
At least 15-20 diagrams: ray diagrams for mirrors/lenses, microscope/telescope, AC generator, transformer, full-wave rectifier, transistor amplifier, cyclotron, Van de Graaff generator, Young’s double-slit, p-n junction V-I characteristic. Use a sharp pencil and label all parts clearly.
Q5. What is the best strategy to score 90%+ in Physics?
Phase 1 (4 weeks before exam): Complete all 9 chapter revisions — focus on concepts + derivations. Phase 2 (2 weeks): Solve 5 previous year papers in exam conditions. Phase 3 (last week): Revise formula sheets, practice diagrams, attempt mock tests. Key tip: Write answers in point-wise format with underlining for keywords — examiners award marks for presentation.
Class 12 Physics Study Strategy & Preparation Tips for
Are you preparing for the MP Board Class 12 Physics board exam 2027 and feeling overwhelmed by the vast syllabus? Physics is often considered one of the most challenging subjects in the Class 12 curriculum, but with the right study strategy, smart planning, and consistent practice, you can easily score 80+ marks. This comprehensive guide covers everything — from chapter-wise weightage and important topics to formula revision techniques and time management tips. Whether you are studying from NCERT or MP Board textbooks, this blog will help you build a winning preparation plan.
Knowing the chapter-wise weightage is the first step to smart preparation. The MP Board Class 12 Physics paper is divided into two books — Physics Part 1 and Physics Part 2. Some chapters carry more marks and should be prioritized. Below is the detailed breakdown:
Unit / Chapter
Weightage
Key Topics
Electrostatics (Ch 1 & 2)
12–15 marks
Coulomb’s law, Electric field, Gauss theorem, Capacitors
Current Electricity (Ch 3)
10–12 marks
Ohm’s law, Kirchhoff’s laws, Wheatstone bridge, Meter bridge
Magnetism & Matter (Ch 4 & 5)
10–12 marks
Biot-Savart law, Ampere’s law, Earth’s magnetism
EMI & AC (Ch 6 & 7)
12–15 marks
Faraday’s law, Lenz’s law, AC circuits, Resonance
Optics (Ch 9 & 10)
14–18 marks
Ray optics, Wave optics, Young’s double slit, Polarisation
With 90 days before the board exam, you can cover the entire Physics syllabus with ample revision time. Here is a week-wise study plan designed for MP Board Class 12 Physics:
📗 Phase 1: Foundation (Days 1–30)
Cover 80% of the theory syllabus with conceptual clarity. Start with high-weightage chapters like Electrostatics, Current Electricity, Magnetism, and Optics. Read NCERT thoroughly — MP Board questions are directly from NCERT. While studying:
Read each chapter from NCERT at least twice
Make your own one-page chapter summary
Solve all NCERT in-text and exercise questions
Watch video lectures for difficult concepts (Electromagnetic Induction, AC)
📘 Phase 2: Numerical & Derivations (Days 31–60)
Focus on numerical problems and important derivations. Physics is all about practice — the more numericals you solve, the better your speed and accuracy. This phase is also when you begin solving previous year papers:
Solve numerical problems from NCERT Examples + back exercises
Practice 20 most important derivations (Gauss law, Lens maker formula, etc.)
Solve MP Board previous year papers from 2020 to 2026
Focus on conversion of units, significant figures, and approximation skills
📕 Phase 3: Revision & Mock Tests (Days 61–90)
The final phase is all about revision and exam simulation. By now you should have completed the entire syllabus:
Take 5 full-length mock tests under timed conditions (3 hours)
Revise all formula sheets daily — at least 30 minutes every morning
Practice diagram-based questions (ray diagrams, circuit diagrams)
Review your weak areas from mock test analysis
🔢 Formula Revision Strategy
Physics formulas are the backbone of numerical problem solving. MP Board exams often have direct formula-based questions. Here is a category-wise formula bank to master:
Category
Key Formulas
Electrostatics
F = kq₁q₂/r², E = F/q, V = kq/r, C = ε₀A/d, U = ½CV²
Current Electricity
V = IR, R = ρL/A, P = I²R, ε = V + Ir, Rₛ = R₁+R₂, 1/Rₚ = 1/R₁+1/R₂
Magnetism
F = qvBsinθ, dB = μ₀Idl×r/4πr³, F = IlB, τ = MBsinθ
EMI & AC
ε = -dΦ/dt, L = μ₀N²A/l, Xʟ = ωL, Xᴄ = 1/ωC, Z = √(R²+(Xʟ-Xᴄ)²)
E = hf, E = mc², λ = h/mv, r = n²r₀, 1/λ = R(1/n₁²−1/n₂²), N = N₀e⁻λᵗ
💡 Pro Tip for Formula Mastery
Create a formula flashcard booklet for each unit. Write formulas on one side and the SI units on the other. Spend 15–20 minutes daily just reading through these cards — especially the ones you find difficult to remember.
🧮 Numerical Problems — Tips & Tricks
Numerical problems carry significant weight in the MP Board Physics exam. With the right approach, you can solve them accurately and quickly:
Read the question carefully — Identify given data and what is asked. Write down all known values with their SI units.
Choose the correct formula — Relate the given and asked quantities. Write the formula first with symbols, then substitute values.
Unit consistency — Convert all values to SI units before substitution. Common mistakes: cm → m, km → m, g → kg.
Show step-by-step calculation — MP Board awards step-wise marks. Even if final answer is wrong, correct steps get partial credit.
Practice daily — Solve at least 5 numericals every day. Focus on Optics, Electrostatics, and Current Electricity chapters which have most numericals.
🔥 Most Common Numerical Types in MP Board Physics
Chapter
Numerical Type
Frequency
Electrostatics
Force between charges, Capacitance of parallel plate capacitor
Very High
Current Electricity
Resistance combination, Kirchhoff’s law, Meter bridge balancing
Very High
Magnetism
Magnetic field due to wire/loop, Force on current carrying conductor
High
EMI & AC
Induced emf, AC circuit impedance, Transformer ratio
High
Optics
Lens & mirror formula, Magnification, Fringe width in YDSE
Very High
📝 Important Derivations & Diagrams
MP Board Physics paper includes at least 3–4 derivation questions carrying 3–5 marks each. These are high-scoring if you present them systematically:
🔑 Must-Know Derivations for MP Board
Coulomb’s law in vector form and principle of superposition
Gauss theorem and its application to infinite wire, sheet, spherical shell
Expression for capacitance of a parallel plate capacitor (with & without dielectric)
Wheatstone bridge — principle and balanced condition
Biot-Savart law and magnetic field on axis of a circular loop
Faraday’s law of EMI and expression for induced emf
Lens maker’s formula and mirror formula
Young’s double slit experiment — expression for fringe width
Einstein’s photoelectric equation and experimental verification
Bohr’s model — radius and energy of electron in nth orbit
🎯 Exam Tip: When writing derivations in the exam, always draw the labeled diagram first (even if not asked). This shows the examiner you understand the concept. For each step, write a brief explanation — don’t just show equations. MP Board examiners give partial marks for correct steps even if the final expression is slightly off.
📄 Previous Year Papers Analysis
Analyzing previous year question papers is the most effective way to understand the exam pattern, marking scheme, and commonly repeated questions. Here is what the last 5 years of MP Board Physics papers reveal:
Year
Total Marks
Numerical Qs
Derivation Qs
Diagram Qs
2025
100
7
4
3
2024
100
6
5
3
2023
100
8
4
4
2022
100
7
3
3
2020
100
6
5
3
Key patterns observed: Optics, Electrostatics, and Modern Physics have the most repeated questions. Numericals from Current Electricity and Optics appear every year without fail. Diagram questions are mandatory — always practice drawing lens ray diagrams, circuit diagrams, and transistor configurations.
⏰ Exam Hall Time Management
Managing time in the examination hall is as important as preparation. Here is an optimal time allocation strategy for the MP Board Class 12 Physics paper (3 hours, 100 marks):
First 15 minutes — Read the entire paper carefully. Identify which questions you are confident about and mark them.
Next 90 minutes — Attempt all 2-mark and 3-mark questions first. These are quick and build momentum.
Next 60 minutes — Solve numericals and derivations (5-mark questions). Show complete steps.
Last 15 minutes — Review your answers. Check for calculation errors, missing units, and unlabeled diagrams.
🎯 Exam Tip: Never leave a question unanswered. If you cannot fully solve a numerical, write the correct formula, the given data with conversion, and the first step — you will get partial credit. For theory questions, write in bullet points with diagrams whenever possible. MP Board examiners reward presentation!
📚 Best Resources & Reference Books
Choosing the right study resources can significantly impact your exam performance. For MP Board Class 12 Physics, here are the recommended books and materials:
Book/Resource
Purpose
Rating
NCERT Physics (Part 1 & 2)
Primary textbook — cover all concepts
⭐⭐⭐⭐⭐
MP Board Previous Year Papers
Exam pattern & repeated questions
⭐⭐⭐⭐⭐
HC Verma (Concepts of Physics)
Advanced numerical practice
⭐⭐⭐⭐
Xam Idea / U-Like Physics
MP Board-specific question banks
⭐⭐⭐⭐
mpboard.ai Physics Notes
Chapter-wise notes & study guides
⭐⭐⭐⭐⭐
💡 Final Tip: The Power of Daily Revision
The most successful MP Board toppers follow one golden rule — revise what you studied yesterday before starting today’s topic. Spend the first 30 minutes of each study session reviewing formulas, derivations, and concepts from the previous day. This simple habit dramatically improves long-term retention. Combine this with solving at least one previous year paper every week, and you are guaranteed to score 80+ in Physics!
MP Board Class 12 Physics Previous Year Questions 2027 — Master every chapter with chapter-wise solved PYQs from 2016–2026 board exams. Physics in Class 12 MP Board carries 70 marks theory + 30 marks practical. The question paper is divided into 5 sections: A (Very Short Answer — 1 mark each), B (Short Answer — 1 mark each), C (Short Answer — 2 marks each), D (Long Answer — 3 marks each), and E (Long Answer — 4/5 marks each). This PYQ compilation covers all chapters with actual board exam questions, marking schemes, and expert solutions.
This chapter covers Coulomb’s law, electric field intensity, electric dipole, Gauss’s law and its applications. Weightage: 5-7 marks in board exam.
📝 Very Short Answer Questions (1 mark)
Q (2023-A): State Coulomb’s law in vector form.
Q (2024-A): What is the SI unit of electric flux?
Q (2022-A): Define electric dipole moment.
Q (2025-A): What is the net flux through a closed surface enclosing no charge?
Q (2023-B): Write the dimensional formula of electric field.
🎯 Exam Tip: Memorize the statement and mathematical expression of Coulomb’s law, Gauss’s law, and the definition of electric dipole moment — these are repeated every year in Section A.
📝 Short Answer Questions (2-3 marks)
Q (2023-A): Derive an expression for the electric field intensity at a point on the axial line of an electric dipole.
Q (2024-A): Using Gauss’s theorem, derive the electric field due to an infinitely long straight uniformly charged wire.
Q (2025-A): Two point charges +4 μC and -4 μC are placed 10 cm apart. Find the electric field at the midpoint of the line joining them.
📝 Long Answer Questions (4-5 marks)
Q (2024-A): State and prove Gauss’s theorem. Using it, derive the electric field intensity due to a uniformly charged spherical shell at (i) inside (ii) on the surface (iii) outside points.
Q (2023-B): Derive an expression for the torque experienced by an electric dipole placed in a uniform electric field. When is the torque maximum and minimum?
🔋 Chapter 2: Electrostatic Potential and Capacitance
Q (2023-A): What is a dielectric? Give one example.
Q (2025-A): Write the SI unit of capacitance.
Q (2022-B): What is the net capacitance of two identical capacitors in series?
📝 Short Answer Questions (2-3 marks)
Q (2024-A): Derive the expression for the capacitance of a parallel plate capacitor with a dielectric medium between the plates.
Q (2023-A): Three capacitors of 2 μF, 3 μF, and 6 μF are connected in series. Find the equivalent capacitance.
Q (2025-B): Draw equipotential surfaces for a point charge and a uniform electric field.
📐 Key Formula
C = ε₀A/d (parallel plate capacitor without dielectric) C = Kε₀A/d (with dielectric) 1/Cs = 1/C₁ + 1/C₂ + 1/C₃ (series) Cp = C₁ + C₂ + C₃ (parallel)
📝 Long Answer Questions (4-5 marks)
Q (2023-A): Derive an expression for the energy stored in a parallel plate capacitor. Also derive the expression for energy density.
Q (2024-A): State the principle of a capacitor. Derive the expression for capacitance of a parallel plate capacitor when a dielectric slab is partially introduced.
Draw the truth table and circuit for NAND and NOR gates as universal gates.
3
2024-A
Distinguish between intrinsic and extrinsic semiconductors.
2
❓ Frequently Asked Questions
Q: How many total marks is the MP Board Class 12 Physics paper?
Ans: The theory paper is of 70 marks, consisting of 5 sections (A-E). Practical exam is 30 marks, making the total 100 marks.
Q: Which chapters have the highest weightage in Class 12 Physics?
Ans: Ray Optics (7-9 marks), Current Electricity (6-9 marks), Electrostatic Potential (6-8 marks), Semiconductor Electronics (6-8 marks), and Electromagnetic Induction (5-7 marks) are the highest weightage chapters.
Q: Are numerical problems important in MP Board Class 12 Physics?
Ans: Yes, numerical problems carry approximately 25-30 marks across all sections. Important numerical topics include: Coulomb’s law, capacitors, Ohm’s law, potentiometer, AC circuits, lens formula, prism formula, radioactive decay, and photoelectric effect.
Q: How many derivations are asked from Physics in board exams?
Ans: Generally 6-8 derivation questions appear (25-30 marks). Important derivations: Gauss’s theorem, electric dipole field, capacitance of parallel plate capacitor, Kirchhoff’s laws, Biot-Savart law, lens maker’s formula, compound microscope, Bohr’s radius, and radioactive decay.
Q: How should I prepare Section A (Very Short Answer)?
Ans: Section A has 10 questions of 1 mark each. Focus on definitions, SI units, laws/statements, and basic formulas. Use NCERT textbook — 90% of Section A questions come directly from NCERT definitions and statements.
Q: Are diagrams compulsory in Physics board exam?
Ans: Yes, labelled diagrams carry specific marks in Long Answer questions. Important diagrams: electric field lines, capacitor, Wheatstone bridge, moving coil galvanometer, AC generator, transformer, prism, compound microscope, telescope, YDSE pattern, p-n junction, energy level diagram, logic gates.
Q: Can I score 70/70 in Physics if I solve all previous year papers?
Ans: Solving PYQs alone covers ~60-65% of the paper (repeated questions). For full marks, also study NCERT textbook thoroughly, practice numerical problems, memorize derivations, and learn diagram drawing. Combining PYQs + NCERT + numerical practice is the winning formula.
Q: How many sets are there in MP Board Physics paper?
Ans: MP Board typically has 4 sets (A, B, C, D) for the Physics paper. All sets follow the same syllabus and pattern but have different question arrangements. Solve all sets for thorough preparation.
Q: Where can I download MP Board Class 12 Physics previous year papers?
Ans: Visit mpboard.ai for chapter-wise PYQ compilation, full previous year papers from 2016-2026, marking schemes, and expert solutions — all in one place.
🎯 Conclusion
Mastering MP Board Class 12 Physics requires consistent practice with previous year questions. This chapter-wise PYQ compilation covers all 14 chapters with actual board exam questions from 2016 to 2026. By solving these questions regularly, you’ll understand the exam pattern, marking scheme, and repeated question trends.
Remember: Physics in board exams is about clear concepts + practice + neat diagrams. Use this PYQ compilation as your daily revision tool. Focus on high-weightage chapters first (Ray Optics, Current Electricity, Semiconductor), then cover all chapters systematically. Best of luck for your MP Board 2027 Physics exam! 💪
Chapter 11: Dual Nature of Radiation and Matter is one of the most important chapters in the MP Board Class 12 Physics syllabus for the 2026 BOARD YEAR exam. This chapter bridges classical and quantum physics, introducing revolutionary concepts like the photoelectric effect, de Broglie wavelength, and wave-particle duality. Below are comprehensive revision notes, key formulas, and tables for quick reference.
Key Concepts at a Glance
This chapter deals with the dual nature of light — it behaves both as a wave (interference, diffraction) and as a particle (photoelectric effect, Compton effect). The same dual nature applies to matter particles like electrons (de Broglie hypothesis).
1. Photoelectric Effect
When light of sufficient frequency falls on a metal surface, electrons are emitted. Key experimental observations:
No electrons are emitted if the incident frequency is below a threshold frequency (f0), regardless of intensity.
Kinetic energy of emitted electrons increases linearly with frequency, not intensity.
Emission is instantaneous — no time lag.
Number of emitted electrons is proportional to intensity of incident light.
Einstein’s Photoelectric Equation
E = hf = phi + K.E.max
Symbol
Quantity
Unit
E = hf
Energy of incident photon
eV or J
phi = hf0
Work function of the metal
eV or J
K.E.max = eV0
Maximum kinetic energy of photoelectron
eV or J
f0
Threshold frequency
Hz
lambda0 = c/f0
Threshold wavelength
m
V0
Stopping potential
V (volt)
Also: K.E.max = eV0 = hf – phi = h(f – f0)
2. Important Formulas
Formula
Description
E = hf = hc/lambda
Energy of a photon (Planck’s relation)
p = h/lambda
Momentum of a photon
K.E.max = hf – phi
Einstein’s photoelectric equation
V0 = (h/e)f – phi/e
Stopping potential vs frequency (linear)
lambda = h/p = h/mv
de Broglie wavelength of a particle
lambda = h / sqrt(2mqV)
de Broglie wavelength of accelerated electron
lambda = h / sqrt(2m(K.E.))
de Broglie wavelength from kinetic energy
d = lambda / (2 sin-theta)
Davisson-Germer: crystal spacing from diffraction
hf = hf’ + K.E.
Compton effect (photon scattering)
delta-lambda = h/(m0c) (1 – cos-phi)
Compton shift (lambda’ – lambda)
3. Important Constants
Constant
Symbol
Value
Planck’s constant
h
6.63 x 10^-34 J.s
h
4.14 x 10^-15 eV.s
Speed of light
c
3 x 10^8 m/s
Electron charge
e
1.6 x 10^-19 C
Electron mass
me
9.1 x 10^-31 kg
Compton wavelength
h/(m0c)
2.43 x 10^-12 m
1 eV
—
1.6 x 10^-19 J
4. Experimental Devices and Discoveries
Experiment
Scientist(s)
Key Finding
Photoelectric effect
Hertz, Hallwachs, Lenard
Light ejects electrons from metal
Photoelectric equation
Einstein (1905)
Light consists of photons; E = hf – phi
Davisson-Germer experiment
Davisson and Germer (1927)
Electrons show diffraction — proof of wave nature of matter
de Broglie hypothesis
Louis de Broglie (1924)
Every moving particle has a wavelength lambda = h/p
Compton effect
Compton (1923)
X-ray photon wavelength increases after scattering
5. Wave-Particle Duality Summary
Phenomenon
Nature of Light
Explanation
Interference, Diffraction
Wave
Requires superposition and phase
Photoelectric effect
Particle (photon)
Energy transfer in discrete quanta
Compton scattering
Particle
Momentum transfer like billiard balls
Polarisation
Wave (transverse)
Electric field oscillation direction
Reflection, Refraction
Both
Explained by both models
6. Quick Revision One-Liners
Stopping potential (V0) depends only on frequency, not intensity.
Saturation current increases with intensity of incident light.
Work function (phi) is the minimum energy needed to eject an electron.
Threshold frequency (f0) = phi/h. Below this, no photoelectric emission.
Photoelectric effect can NOT be explained by wave theory — validates particle nature.
Davisson-Germer experiment confirmed de Broglie’s hypothesis experimentally.
de Broglie wavelength of a macroscopic object is negligible.
Photon rest mass = 0. Photon always travels at speed c.
Momentum of photon p = h/lambda = E/c.
Slope of V0 vs f graph = h/e (Planck’s constant / electron charge).
7. Solved Example
Q: The work function of cesium metal is 2.14 eV. Find (a) threshold wavelength, (b) maximum kinetic energy of photoelectrons when light of wavelength 4000 Angstrom is incident, (c) stopping potential.
Solution:
(a) phi = 2.14 eV = 2.14 x 1.6 x 10^-19 = 3.424 x 10^-19 J lambda0 = hc/phi = (6.63×10^-34 x 3×10^8) / 3.424×10^-19 = 5.81 x 10^-7 m = 5810 Angstrom
(b) E = hc/lambda = (6.63×10^-34 x 3×10^8) / (4000×10^-10) = 4.97 x 10^-19 J = 3.10 eV K.E.max = E – phi = 3.10 – 2.14 = 0.96 eV
(c) eV0 = K.E.max implies V0 = 0.96 / 1 = 0.96 V
Key Exam Tips for BOARD YEAR 2026
Einstein’s photoelectric equation is the MOST frequently asked derivation.
Numerical problems from photoelectric effect and de Broglie wavelength are common.
Know the definitions of threshold frequency, work function, and stopping potential.
Davisson-Germer experiment — diagram + explanation is a popular 5-mark question.
de Broglie hypothesis and its experimental verification — must know.
Compton effect derivation is usually asked for 2-3 marks.
—
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Class 12 Physics Solved Paper 2025 MPB – Previous Ye…
MP Board Class 12 Physics Solved Paper 2025 – Complete Solution with Question-by-Question Analysis
The MP Board Class 12 Physics exam 2025 was conducted by the Madhya Pradesh Board of Secondary Education (MPBSE). This solved paper provides step-by-step solutions to all questions asked in the 2025 board examination. Each question includes the correct answer, detailed reasoning, and marking scheme based on the official MP Board pattern.
📋 Exam Overview – MP Board Class 12 Physics 2025
Particular
Details
Board
Madhya Pradesh Board of Secondary Education (MPBSE)
Subject
Physics (Subject Code: 203)
Exam Year
2025
Total Marks
100
Time Duration
3 Hours
Total Questions
24 (Group A: 5, Group B: 5, Group C: 6, Group D: 4, Group E: 4)
📝 Group A: Very Short Answer Type Questions (5 × 2 = 10 Marks)
Question 1: Define electric dipole moment. Write its SI unit and direction.
Solution: Electric dipole moment is defined as the product of the magnitude of either charge and the distance between the charges. Mathematically: p = q × 2a. Its SI unit is Coulomb-metre (C·m). The direction of electric dipole moment is from negative charge to positive charge along the dipole axis.
Marking Scheme: Definition (1 mark), SI unit and direction (1 mark).
Question 2: State Coulomb’s law in electrostatics. Write the expression for force between two point charges.
Solution: Coulomb’s law states that the electrostatic force between two point charges is directly proportional to the product of their magnitudes and inversely proportional to the square of the distance between them. The force acts along the line joining the two charges.
F = k × (q₁ × q₂) / r²
where k = 1/(4πε₀) = 9 × 10⁹ N·m²/C², q₁ and q₂ are the charges, and r is the distance between them.
Marking Scheme: Statement of law (1 mark), correct formula (1 mark).
Question 3: What is meant by the term ‘depletion region’ in a p-n junction diode?
Solution: The depletion region is a narrow region near the p-n junction that is depleted of free charge carriers (electrons and holes). It contains only immobile ions — positively charged donor ions on the n-side and negatively charged acceptor ions on the p-side. This creates an electric field across the junction that acts as a barrier for further diffusion of majority carriers.
Marking Scheme: Concept of charge-free region (1 mark), immobile ions and electric field (1 mark).
Question 4: Two charges 5 µC and −3 µC are placed 2 cm apart. Calculate the force between them.
Solution: Using Coulomb’s law:
F = k × |q₁ × q₂| / r²
Here, q₁ = 5 × 10⁻⁶ C, q₂ = −3 × 10⁻⁶ C, r = 2 × 10⁻² m, k = 9 × 10⁹ N·m²/C²
The force is attractive (since charges are opposite).
Answer: 337.5 N, Attractive
Marking Scheme: Correct formula with values (1 mark), correct answer (1 mark).
Question 5: What is the angle between electric field and dipole moment when the dipole is in (i) stable equilibrium, and (ii) unstable equilibrium?
Solution: (i) For stable equilibrium, the angle between electric field (E) and dipole moment (p) is 0° (parallel). (ii) For unstable equilibrium, the angle is 180° (anti-parallel).
Marking Scheme: Correct angle for stable (1 mark), correct angle for unstable (1 mark).
📝 Group B: Short Answer Type Questions I (5 × 3 = 15 Marks)
Question 6: Explain the principle of a capacitor. Derive the expression for capacitance of a parallel plate capacitor.
Solution: A capacitor stores electrical energy in an electric field. The capacitance C = Q/V, where Q is the charge stored and V is the potential difference.
For a parallel plate capacitor with plate area A and plate separation d:
The electric field between the plates: E = σ/ε₀ = Q/(A·ε₀)
Potential difference: V = E·d = (Q·d)/(A·ε₀)
Capacitance: C = Q/V = (ε₀·A)/d
If a dielectric of relative permittivity εᵣ is inserted: C = (ε₀·εᵣ·A)/d = (ε·A)/d
Marking Scheme: Principle (1 mark), derivation without dielectric (1 mark), derivation with dielectric (1 mark).
Question 7: State Kirchhoff’s laws for electrical circuits. Apply them to find the current in a Wheatstone bridge and state the condition for balance.
Solution:Kirchhoff’s Current Law (KCL): The algebraic sum of currents meeting at a junction is zero. Kirchhoff’s Voltage Law (KVL): The algebraic sum of potential differences in any closed loop is zero.
For a Wheatstone bridge with resistors P, Q, R, S arranged in four arms, the bridge is balanced when no current flows through the galvanometer. Applying KVL:
Balance condition: P/Q = R/S
Marking Scheme: KCL and KVL statements (1 mark each), balance condition (1 mark).
Question 8: Derive the expression for magnetic field at the centre of a circular current-carrying loop.
Solution: Consider a circular loop of radius R carrying current I. Using Biot-Savart’s law:
dB = (μ₀/4π) × (I·dl × r̂)/r²
At the centre, distance r = R for all elements. dl ⟂ r̂ for all elements. Magnitude:
B = ∫dB = (μ₀/4π) × (I·dl)/R²
Integrating dl around the loop: ∫dl = 2πR
B = (μ₀/4π) × (I·2πR)/R² = μ₀I/(2R)
Direction: perpendicular to the plane of the loop (right-hand thumb rule).
Marking Scheme: Biot-Savart law with correct formula (1 mark), integration steps (1 mark), final expression (1 mark).
Question 9: A convex lens of focal length 20 cm forms an image at 60 cm from the lens on the other side. Find the object distance and magnification.
Solution: Using lens formula: 1/f = 1/v − 1/u
Given: f = +20 cm (convex lens), v = +60 cm (real image on other side)
1/20 = 1/60 − 1/u
1/u = 1/60 − 1/20 = (1 − 3)/60 = −2/60 = −1/30
u = −30 cm (object is 30 cm in front of the lens — negative sign indicates real object)
Magnification: m = v/u = 60/(−30) = −2
The image is real, inverted, and magnified 2 times.
Question 10: Write three differences between p-type and n-type semiconductors.
Solution:
Property
p-type Semiconductor
n-type Semiconductor
Majority Carriers
Holes (positive charge)
Electrons (negative charge)
Dopant Added
Trivalent impurity (B, Al, Ga, In)
Pentavalent impurity (P, As, Sb)
Fermi Level Position
Near valence band
Near conduction band
Marking Scheme: Each correct difference (1 mark).
📝 Group C: Short Answer Type Questions II (6 × 5 = 30 Marks)
Question 11: State Gauss’s law in electrostatics. Apply it to derive the electric field due to an infinitely long straight uniformly charged wire.
Solution: Gauss’s law states that the total electric flux through a closed surface is equal to the net charge enclosed divided by ε₀.
∮E·dA = Q_enclosed/ε₀
Consider a Gaussian cylinder of radius r and length L coaxial with the wire carrying linear charge density λ. By symmetry, E is radial and constant on the curved surface. Flux through curved surface: E × 2πrL. Flux through end caps: 0 (E ⟂ dA). Charge enclosed: λL.
E × 2πrL = λL/ε₀
E = λ/(2πε₀r)
Direction: radially outward (for positive λ).
Marking Scheme: Gauss law statement (1 mark), Gaussian surface selection (1 mark), derivation steps (2 marks), final expression (1 mark).
Question 12: Derive the expression for the magnetic force on a current-carrying conductor placed in a uniform magnetic field. When is this force maximum and minimum?
Solution: For a conductor of length L carrying current I in a magnetic field B at angle θ to the field:
F = I·L·B·sinθ
This is derived from the Lorentz force on moving charges: each charge q moving with drift velocity vd experiences FB = q·vd·B·sinθ. For n charges per unit volume in volume A·L:
F = n·A·L·q·v·B·sinθ = (n·A·q·v)·L·B·sinθ = I·L·B·sinθ
Force is maximum when θ = 90° (conductor perpendicular to B). Force is minimum (zero) when θ = 0° or 180° (conductor parallel to B).
Marking Scheme: Derivation using Lorentz force (3 marks), max condition (1 mark), min condition (1 mark).
Question 13: With a labeled diagram, explain the principle and working of a transformer. Derive the relationship between input and output voltages.
Solution: A transformer works on the principle of mutual induction — an alternating current in the primary coil produces a changing magnetic flux that induces an alternating emf in the secondary coil.
[Diagram: Core with primary coil (NP turns) on left, secondary coil (NS turns) on right, AC source across primary, load across secondary]
If the magnetic flux through each turn is Φ(t) = Φ₀·sin(ωt):
Induced emf in primary: EP = −NP·dΦ/dt
Induced emf in secondary: ES = −NS·dΦ/dt
Dividing: ES/EP = NS/NP
For an ideal transformer (100% efficiency): VS/VP = NS/NP = IP/IS
Question 14: Derive the lens maker’s formula for a thin lens.
Solution: The lens maker’s formula relates the focal length of a lens to its radii of curvature and refractive index.
Consider a thin lens with radii R₁ and R₂, refractive index n₂ surrounded by medium n₁. For refraction at the first surface:
n₂/v₁ − n₁/u = (n₂−n₁)/R₁ … (1)
For the second surface, v₁ acts as virtual object for second surface:
n₁/v − n₂/v₁ = (n₁−n₂)/R₂ = −(n₂−n₁)/R₂ … (2)
Adding (1) and (2):
n₁/v − n₁/u = (n₂−n₁)(1/R₁ − 1/R₂)
For u = ∞, v = f (focal length):
1/f = (n₂/n₁ − 1)(1/R₁ − 1/R₂)
If surrounding medium is air (n₁ = 1) and μ = n₂:
1/f = (μ−1)(1/R₁ − 1/R₂)
Marking Scheme: Refraction at first surface (2 marks), refraction at second surface (2 marks), final formula (1 mark).
📝 Group D: Long Answer Type Questions (4 × 5 = 20 Marks)
Question 15: What is photoelectric effect? Derive Einstein’s photoelectric equation. Mention any two experimental results that cannot be explained by wave theory.
Solution: The photoelectric effect is the emission of electrons from a metal surface when electromagnetic radiation of sufficient frequency falls on it.
Einstein proposed that light consists of quanta (photons) each with energy E = hν. The maximum kinetic energy of emitted electrons:
Kmax = hν − ϕ
where hν is photon energy and ϕ is the work function of the metal. If ν₀ is threshold frequency: ϕ = hν₀
½·m·Vmax² = hν − hν₀ = h(ν − ν₀)
Two results unexplained by wave theory:
The existence of a threshold frequency below which no photoelectrons are emitted, regardless of intensity.
The instantaneous emission of photoelectrons — there is no time lag between light incidence and electron emission.
Marking Scheme: Concept of photoelectric effect (1 mark), Einstein equation derivation (2 marks), experimental results (2 marks).
Question 16: State and prove the principle of conservation of energy in the case of electromagnetic induction (Lenz’s law).
Solution: Lenz’s law states that the direction of induced current is always such that it opposes the cause producing it. This is a consequence of the law of conservation of energy.
Proof: Consider a magnet moving towards a coil. The induced current in the coil produces a magnetic field that repels the magnet. To continue moving the magnet toward the coil, external work must be done against this repulsive force. This mechanical work is converted into electrical energy in the coil. If the induced current aided the motion, energy would be created from nothing — violating conservation of energy.
Mathematically: Faraday’s law gives ε = −dΦ/dt. The negative sign (Lenz’s law) ensures the energy is conserved — the electrical energy generated equals the mechanical work done.
Marking Scheme: Statement of Lenz’s law (1 mark), explanation of energy conservation (2 marks), mathematical proof (2 marks).
📝 Group E: Numerical Questions (4 × 5 = 20 Marks)
Question 17: A sinusoidal voltage V(t) = 200·sin(314t) is applied to a series LCR circuit with R = 10 Ω, L = 0.1 H, C = 50 µF. Calculate: (i) Impedance, (ii) Current, (iii) Resonant frequency.
Marking Scheme: Each part: correct formula (1 mark each), correct answer (remaining marks).
⭐ Key Topics to Focus On for 2027 Exam
Based on the 2025 paper analysis, students preparing for the 2027 MP Board Class 12 Physics exam should focus on:
Electrostatics (Gauss law, Coulomb’s law, capacitors): 15-20 marks
Current Electricity (Kirchhoff’s laws, Wheatstone bridge): 10-12 marks
Magnetic Effects (Biot-Savart, force on conductor): 12-15 marks
Optics (Lens formula, lens maker formula): 12-15 marks
Electromagnetic Induction (Faraday, Lenz, transformer): 10-12 marks
Modern Physics (Photoelectric effect, semiconductors): 10-12 marks
Total: ~70-85 marks from these core topics — focus on numerical problems (30% weightage).
📌 Tip: Practice derivations and numerical problems daily. At least 40% of the paper requires step-by-step derivation skills — writing the correct formula earns half the marks!
Disclaimer: This solved paper is based on memory-based reconstruction of the MP Board Class 12 Physics 2025 exam. Questions are representative of the actual exam pattern and marking scheme. For official question papers, visit the MPBSE website.
