Class 12 Physics is an important subject, especially for students preparing for board exams and entrance tests like JEE or NEET. It includes topics like electricity, magnetism, optics, and modern physics, which need clear understanding and practice. One of the best ways to prepare well is by solving Class 12 Physics  important questions from each chapter. These questions are chosen carefully and often cover the key concepts asked in exams. 

Solving them helps students improve their thinking skills, understand the types of questions asked, and manage their time during exams. Numerical problems also help in learning how to apply formulas and solve real problems.

Practicing these questions regularly makes students more confident and reduces exam fear. That’s why solving important Physics questions is very useful and should be a part of every student’s study plan.

Class 12 Physics Chapter Wise Important Questions

Following are class 12 Physics important questions that you should mandatorily practice before exam:

Chapter 1: Electric Charges and Fields

1. Explain Gauss's law and derive the expression for electric field due to a uniformly charged spherical shell.
   
   
2. A point charge of +2 μC is placed at the origin. Calculate the flux of the electric field through a sphere of radius 10 cm centered at the origin.
   
   
3. A charge of +Q is placed at each corner of a square. Calculate the electric potential at the center of the square.
   
   

Chapter 2: Electrostatic Potential and Capacitance

1. Derive the expression for the capacitance of a parallel plate capacitor with a dielectric slab of thickness t and dielectric constant κ inserted between the plates.
   
   
2. Calculate the energy stored in a capacitor of capacitance 10 μF charged to a potential difference of 100 V.
   
   
3. A parallel plate capacitor has a capacitance of 20 μF and is connected to a battery of 50 V. Calculate the charge on each plate and the energy stored in the capacitor.
   
   

Chapter 3: Current Electricity

1. Derive the expression for drift velocity of electrons in a conductor in terms of applied electric field and relaxation time.
   
   
2. Calculate the resistivity of a conductor whose resistance is 2 Ω and length is 5 m, and cross-sectional area is 3×10−63 \times 10^{-6} m².
   
   
3. Two resistors of 4 Ω and 6 Ω are connected in series with a 12 V battery. Calculate the current flowing through each resistor.
   
   

Chapter 4: Moving Charges and Magnetism

1. Derive the expression for the magnetic field at a point on the axis of a circular current-carrying loop.
   
   
2. A current of 5 A flows through a circular coil of radius 10 cm. Calculate the magnetic field at the center of the coil.
   
   
3. A conducting rod of length 2 m moves with a velocity of 5 m/s perpendicular to a uniform magnetic field of 0.2 T. Calculate the induced emf between its ends.
   
   

Chapter 5: Magnetism and Matter

1. Explain the phenomenon of magnetic hysteresis and draw the hysteresis loop for a ferromagnetic material.
   
   
2. Calculate the magnetic susceptibility of a paramagnetic substance placed in a magnetic field of intensity 100 A/m.
   
   
3. A magnetic needle vibrates with a period of 4 seconds. If the horizontal component of Earth's magnetic field is 0.4 G, calculate the moment of inertia of the needle.
   
   

Chapter 6: Electromagnetic Induction

1. Derive Faraday's law of electromagnetic induction and Lenz's law.
   
   
2. A rectangular coil of dimensions 0.1 m × 0.2 m with 100 turns is rotated at 50 revolutions per second in a magnetic field of 0.5 T. Calculate the induced emf.
   
   
3. A 20 Ω resistor is connected to the secondary coil of a transformer whose primary has 100 turns and operates at 220 V. Calculate the current in the resistor.
   
   

Chapter 7: Alternating Current

1. Derive the expression for the average power dissipated in an AC circuit containing only resistors.
   
   
2. Calculate the inductive reactance of a coil with inductance 0.02 H when connected to a 50 Hz AC source.
   
   
3. A series LCR circuit has a resistance of 10 Ω, inductance of 0.1 H, and capacitance of 50 μF. Calculate the impedance and resonant frequency of the circuit.
   
   

Chapter 8: Electromagnetic Waves

1. Derive the expression for the displacement current in Maxwell's equations.
   
   
2. Calculate the speed of electromagnetic waves in a medium with relative permittivity ϵr=4\epsilon_r = 4 and relative permeability μr=2\mu_r = 2.
   
   
3. A radio station broadcasts at a frequency of 100 MHz. Calculate the wavelength of the radio waves in vacuum.
   
   

Chapter 9: Ray Optics and Optical Instruments

1. Derive the lens maker's formula and explain how it is used to find the focal length of a lens.
   
   
2. Calculate the magnifying power of a simple microscope with a focal length of 5 cm and an eyepiece of focal length 10 cm.
   
   
3. A glass prism of refractive index 1.5 is immersed in water (refractive index = 1.33). Calculate the angle of minimum deviation for the prism.
   
   

Chapter 10: Wave Optics

1. Derive the condition for constructive interference in Young's double-slit experiment.
   
   
2. Calculate the angular separation between the first and second bright fringes in a double-slit experiment with slit separation of 0.1 mm and wavelength of light 600 nm.
   
   
3. A plano-convex lens of radius of curvature 20 cm is immersed in a liquid of refractive index 1.5. Calculate the focal length of the lens in the liquid.
   
   

Chapter 11: Dual Nature of Radiation and Matter

1. Derive the de Broglie wavelength of an electron accelerated through a potential difference V.
   
   
2. Calculate the kinetic energy of an electron whose de Broglie wavelength is 1 Å.
   
   
3. Explain the phenomenon of photoelectric emission and derive the Einstein's photoelectric equation.
   
   

Chapter 12: Atoms

1. Derive the expression for Bohr's radius of the hydrogen atom and calculate its value.
   
   
2. Calculate the energy difference between the first and second Bohr orbits of hydrogen atom.
   
   
3. Explain the concept of energy levels in atoms and their significance in spectral lines.
   
   

Chapter 13: Nuclei

1. Derive the expression for the binding energy per nucleon and explain its variation with mass number.
   
   
2. Calculate the energy released in the alpha decay of 238^{238}U to 234^{234}Th.
   
   
3. A radioactive sample has an initial activity of 10610^6 disintegrations per second. Calculate its activity after 10 days, given the half-life is 2 days.
   
   

Chapter 14: Semiconductor Electronics: Materials, Devices, and Simple Circuits

1. Explain the working principle of a p-n junction diode and derive its V-I characteristics.
   
   
2. Calculate the gain in dB of a transistor amplifier with input power 10 mW and output power 1 W.
   
   
3. A silicon diode has a forward resistance of 0.7 V at a current of 10 mA. Calculate its dynamic resistance at this operating point.

Benefits of Solving Class 12 Physics Important Questions Before Exam 

Before exams, it's important to focus on the right kind of preparation.Solving important questions for class 12 Physics with answers PDF is one of the smartest ways to revise effectively. These questions are selected based on frequently asked topics and help students practice both theory and numericals in a focused way.

1. Important questions focus on key topics and help strengthen your understanding of core Physics concepts.
2. Regular practice of theory and numerical questions improves analytical thinking and accuracy.
3. These questions are often based on previous years' trends, helping you understand the question format and marking scheme.
4. Solving timed questions helps you practice completing the paper within the exam duration.
5. Knowing you’ve practiced the most important and challenging questions reduces exam anxiety.
6. Helps you find topics where you need more practice and allows you to focus your revision better.
7. Important questions act as a quick revision guide, saving time before exams.
8. With regular practice, your calculation speed and accuracy improve significantly.
9. These questions also prepare you for entrance exams like JEE and NEET.
10.  Focused practice increases the chances of scoring high marks in the board exams.

Solving important questions is a smart way to prepare well for exams. These 12th Physics important questions with answers PDF focus on the most important topics and help students revise in a better way.

Regular practice improves understanding, increases speed and accuracy, and helps students learn how to solve both theory and numerical problems. It also helps them avoid common mistakes and feel more confident while writing exams.

Practicing these questions, students become more familiar with the exam pattern and can handle tough questions easily. It gives students a clear idea of what to expect in the exam and boosts their overall performance.

In simple words, solving Physics important questions regularly is one of the best ways to score better and succeed in your Class 12 journey.