Most of students search over Google for Haryana Board (HBSE) Important Questions 2026. Here is the Main reason because HBSE Board Says that in HBSE Exam 2026 (last 3 Years of Questions will Repeat) so that here are the selected List of Questions of Haryana Board For Class 12.
HBSE Class 12 Physics Important Question Answer 2026
Chapter 1 – Electric Charges and Fields
Q1. State and prove Gauss’s Law in Electrostatics. Most Important
Q2. What are electric field lines? Draw these for a point charge -Q. Most Important
Q3. What is electric flux ? State Gauss’s law for electric flux. Write important points regarding this law. Most Important
Q4. What is Coulomb’s law ? Write its expression. Most Important
Q5. Define Electric flux. Is it a scalar or a vector quantity? Use Gauss’s law to derive the expression for the electric field due to a straight uniformly charged infinite line of charge density λ c/m.
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Obtain an expression for the Intensity of Electric field near a uniformly charged straight wire of Infinite Length, with the help of Gauss’s theorem in Electrostatics.
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Determine electric field intensity near an infinitely long straight uniformly charged wire.
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Obtain an expression for electric field due to an infinite long straight charged wire.
Q6. The force of repulsion between two negatively charged particles is F. When distance between them is halved, what will be the value of this force ?
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The distance between two charged particles is halved. What will be the effect on the force between them?
Q7. Find the expression for electric field intensity E due to uniformly charged spherical shell at a point inside the shell.
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Find the expression for electric field intensity E due to a uniformly charged thin spherical shell at a point inside the shell.
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Deduce expression for electric field intensity due to a uniformly charged thin spherical shell at a point inside the shell.
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State the Gauss’s law of electrostatics. Using it prove that electric field inside a uniformly charged thing spherical shell is zero.
Q8. The force of attraction between a positively charged particle and a negatively charged particle is F. When distance between them is made one fourth, what will be the value of this force ?
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The force of repulsion between two positively charged particles is F. When distance between them is made one fourth, what will be the value of this force ?
Q9. State important properties of electrostatic field lines.
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Two electrostatic field lines never cross each other. Why?
Chapter 2 – Electrostatic Potential and Capacitance
Q1. Three capacitors of capacitances 2 pF, 3 pF and 4 pF are connected in parallel. Determine the charge on each capacitor, if the combination is connected to a 100 V supply ? Most Important
Q2. Write the expression for energy stored in a capacitor in terms of charge and potential difference between its plates. Most Important
Q3. Write expression for capacitance of a parallel plate capacitor and explain the effect of dielectrics on capacitance.
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What is a capacitor? Derive an expression for the capacitance of a parallel plate capacitor in which a dielectric medium of dielectric constant K partially fills the space between the plates. Draw the necessary diagram.
Chapter 3 Current Electricity
Q1. Explain Kirchhoff’s Junction rule. Most Important
Q2. What is Kirchhoff’s loop rule ? Most Important
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Explain the Kirchhoff’s voltage law.
Q3. What is Ohm’s law ? Write its relation. Most Important
Q4. Explain the use of meter bridge for finding an unknown resistance. Most Important
Q5. Write the principle of meter bridge. Draw its circuit diagram to determine the value of an unknown resistance.
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Draw the circuit diagram to determine unknown resistance using metre bridge. Write the equation for determining the unknown resistance. Most Important
Q6. Two unequal resistance are connected in parallel. What is same for them? Most Important
Q7. What is the maximum current that can be drawn from a storage battery of emf 10 V and internal resistance 0.2Ω ? Most Important
Q8. The maximum current that can be drawn from a storage battery of emf 18 V is 30 A. What is its internal resistance ? Most Important
Q9. How much current flows through a 3 kΩ resistor when a potential difference of 9 V is applied across its ends? Most Important
Q10. Explain Wheatstone bridge with the help of a diagram. Most Important
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What is balanced condition of Wheatstone bridge ?
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Draw circuit diagram of a wheat stone bridge and write the expression for the balance condition.
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Define a Wheatstone bridge ? Draw labelled diagram and discuss the balance condition.
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Draw the circuit diagram of a Wheatstone bridge. Derive its balance condition to give null deflection in galvanometer.
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Draw the circuit diagram for Wheatstone bridge to determine unknown resistance. Write condition for balancing of the bridge.
Q11. What do you mean by eddy currents? How it can be produced. Write the name of applications of eddy currents.
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What are Eddy currents? Explain. Most Important
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What are Eddy currents? Write any two applications of Eddy currents.
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Name four applications of Eddy currents.
Q12. Write any two limitations of Ohm’s Law ?
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Write any two conditions when Ohm’s Law fails?
Chapter 4 – Moving Charges and Magnetism
Q1. State Biot-Savart’s Law and write its Mathematical form. Most Important
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State Biot-Savart’s Law using a diagram.
Q2. Explain the principle and working of a Cyclotron. Most Important
Q3. Explain the principle and working of a cyclotron using its schematic sketch. Show that time of revolution of an ion is independent of its speed or radius of its orbit. Most Important
Q4. Diagram of Cyclotron. What type of particles can be accelerated using it? Most Important
Q5. Explain the principle of a moving coil galvanometer. How can it be converted into a voltmeter? Explain with the help of diagram. Most Important
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A Explain the principle of a moving coil Galvanometer. How can it be converted into an ammeter ? Draw necessary diagram. Most Important
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Explain the principle and working of a moving coil galvanometer with the help of a labelled diagram.
Q6. Define ampere circuital law? Write expression for magnetic field at a distance r from a straight infinite wire carrying current I. Which rule is used to determine the direction of this magnetic field?
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State Ampere’s circuital law and explain it briefly using a diagram.
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Using Ampere’s law find an expression for the magnetic field due to a straight long current carrying wire at a distance r outside it.
Chapter 5 – Magnetism and Matter
Q1. What is the value of magnetic permeability of a perfectly diamagnetic substance? Most Important
Q2. What is the value of angle of dip at the Earth’s magnetic poles? Most Important
Q3. Define the term magnetic intensity H and write its unit.
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Write SI Unit of magnetic intensity.
Chapter 6 – Electromagnetic Induction
Q1. Explain the principle, construction,diagram and working of A. C. Generator. Most Important
Q2. Define self and mutual inductance.. Most Important
Q3. Define the coefficient of self-inductance. Most Important
Q4. State Faraday’s law of electromagnetic induction and mathematical form. Most Important
Q5. State Lenz’s law. Most Important
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What is Lenz’s law for electromagnetic induction? Most Important
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Explain, how Lenz’s Law show the conservation of energy in the phenomena of Electromagnetic Induction.
Q6. Write SI Unit of magnetic flux density. Most Important
Chapter 7 – Alternating Current
Q1. A series LCR circuit with R = 40Ω, L = 8H and C = 50 μF is connected to a variable frequency 240 V ac supply. Most Important
(a) What is the angular frequency ω0 of the source at which resonance occurs?
(b) Calculate the impedance and current at resonant condition.
Q2. Explain the principle, diagram and working of a transformer. Most Important
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What is Transformer ? Draw its labelled diagram.
Q3. A series L-C-R circuit with R = 44Ω, C = 8μF and L= 50 H is connected to a variable frequency 220 V ac supply. Calculate angular frequency, impedance and current at resonance condition. Most Important
Q4. Derive an expression for the force between two parallel straight conductors carrying currents in the same direction. Hence define one ampere. Most Most Important
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Obtain an expression for force per unit length between two parallel current carrying conductors. Define 1 ampere.
Q5. What is Inductive reactance ? How it is related to capacitive reactance at resonance?
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What is capacitive reactance? How it is related to inductive reactance at resonance ?
Chapter 8 – Electromagnetic Waves
Q1. Write two uses each of Microwaves, Gamma rays, UV Rays, X-Rays and Radio Waves. Most Important
Q2. Define displacement current and write its mathematical form. Most Important
Q3. The electric field in a plane electromagnetic wave is : Ex = 3.1cos(1.8×10-2 y + 5.4×106 t) Newton/Coulomb. What is the wavelength and frequency of the wave? Most Important
Q4. What are electromagnetic Waves ? What is their nature? Most Important
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What are electromagnetic waves ?
Chapter 9 – Ray Optics and Optical Instruments
Q1. Define power of a lens and give its relation with focal length. Most Important
Q2. Draw a labelled ray diagram showing image formation in an astronomical telescope. Derive expression for its magnifying power. Most Most Important
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Draw ray diagram of an astronomical telescope and define its magnification. Most Important
Q3. Draw a labelled ray diagram showing the formation of image in a compound microscope. Define its magnifying power and write expression for it. Most Most Important
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Draw the ray diagram of a compound microscope and obtain an expression for the magnifying power of microscope, when final image is formed at the least distance of distinct vision. Most Important
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Draw the ray diagram of a compound microscope and define its magnification.
Q4. Monochromatic light is refracted from air into a medium of refractive index n. What is the ratio of the wavelengths of the incident and the refracted waves. Most Important
Q5. Explain total internal reflection by a ray diagram. Most Important
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Define Total Internal Reflection.
Q6. Two thin lenses of power +5 Dioptre and -3 Dioptre are placed in contact. Find the power of this combination. Most Important
Chapter 10 – Wave optics
Q1. What is diffraction of light? Explain the intensity distribution graph due to diffraction from a single slit. Most Important
Q2. Using Huygens’s construction, show how a plane wave is reflected from a surface. Hence verify the law of reflection.Most Important
Q3. Find out the expression for Fringe width in Young’s double slit experiment. Most Important
Q4. In Young’s double-slit experiment the distance between the central bright fringe and the fourth bright fringe is measured to be 1.2 cm. Determine the wavelength of the light used if the slits are separated by 0.28 mm and the screen is placed 1.4 m away. Most Important
Q5. What is polarization of light? Briefly describe polarization by reflection and polarization by scattering of light ? Most Important
Q6. What are coherent sources of light? Derive mathematically the conditions for constructive and destructive interference at an arbitrary point due to two coherent sources in terms of phase difference φ. Most Important
Q7. Is the speed of light in glass independent of the colour of light? (Yes or No) Most Important
Chapter 11 – Dual Nature of Radiations and Matter
Q1. Using Einstein’s photoelectric equation, explain effect of frequency of incident radiation on stopping potential. Most Important
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Draw a graph showing effect of frequency of incident radiation on stopping potential. Explain it by using Einstein’s photoelectric equation.
Q2. If the work function of Caesium is 2.14 eV then find its threshold frequency. Most Important
Q3. What is photoelectric effect? Explain effect of intensity on photoelectric current. Most Important
Q4. Explain effect of potential on photoelectric current. Most Important
Q5. Discuss the variation of photoelectric current with collector plate potential for different frequency of incident radiation.
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Discuss the variation of photocurrent with collector plate potential for different intensity of radiation.
Chapter – 12 Atoms
Q1. Calculate the energy equivalent of 1.6 gram of a substance first in Joules and then in MeV. Most Important
Q2. Discuss the three postulates of Bohr’s model for hydrogen atom. Most Important
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State Bohr Postulates of Hydrogen atom.
Q3. The ground state energy of hydrogen atom is -13.6 eV. Find the kinetic energy and the potential energy of the electron in this state. Most Important
Q4. The mass of an electron is m and has charge e. If this electron is accelerated by a potential difference of V, then write the formula for the de-Broglie wavelength associated with it.
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The mass of a charged particle is m and has charge q. If this particle is accelerated by a potential difference of V, then write the formula for the de-Broglie wavelength Associated with it.
Chapter – 13 Nuclei
Q1. Explain nuclear fission and nuclear fusion and give their uses. Write one example reaction of each. Most Important
Q2. Define mass defect and nuclear binding energy. For a nucleus , write the value of mass defect and nuclear binding energy. Most Important
Q3. A Define the term Half-life period and decay constant of a radioactive element. Write the relation between them. Most Important
Q4. Explain the laws of radioactive decay. Derive an equation of radioactive decay using these laws. Most Important
Q5. What is basic nuclear process underlying B+ decay? Write nuclear reaction of this decay for . Most Important
Q6. How much activity is one Becquerel (1 Bq) ? Most Important
Q7. Write the relation between kinetic energy of a-particle and its distance of closest approach
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Write the relation between kinetic energy of α-Particle and its distance of closest approach from nucleus in Rutherford’s a-scattering experiment.
Chapter 14 – Semiconductor Electronics : Materials, Devices and Simple Circuits
Q1. What are N-type semiconductors ? How they are formed ? Most Important
Q2. Draw the circuit diagram of a half-wave rectifier using two p-n Junction diode. Show wave forms of input and output voltages also. Most Important
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Draw the circuit diagram of Half wave rectifier, showing input and output waves.
Q3. Draw a circuit diagram of a full wave rectifier and explain its output waveform. Most Important
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Draw the circuit diagram of an Full wave rectifier and explain its input and output voltage waveform.
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Draw the circuit diagram of a full wave rectifier using two p-n Junction diode. Draw input, output wave form also.
Q4. What is doping? State two differences between N-type and P-type. Most Important
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What is the difference between P and N-type semiconductors ?
Q5. Explain the use of P-N diode as full wave rectifier.
Q6. Explain the use of P-N diode as half-wave rectifier.