Class 12 Physics Important Questions

As you know the class 12 exam is near. So, for you all, I brought you the some of the most important class 12 physics questions which will definitely help you during your exam. Some of the topics are changes in 2079-80 syllabus. we ready this question according to the new syllabus.

Alert: The question which we provide for you is not guaranteed to asked in your final examinations. But it is the highly chance question to be asked in Final Exam, so it makes your study easier for your exam.


Physics is the branch of science that deals with the structure of matter and the interactions between the fundamental constituents of the observable universe. In the broadest sense, physics (from the Greek physios) is concerned with all aspects of nature on both the macroscopic and submicroscopic levels.

Class 12 Physics Important Questions
Class 12 Physics Important Questions

Physics book are categorized in 5 section.


2.Heat and thermodynamiscs

3.Wave and optics

4.Electricity and magnetism

5.Modern physics

Question from Mechanics

  • Rotational Dynamics
  • Equations of Angular Motions
  • Equations of linear motion
  • Radius of Gyration
  • DEVIVATION-Rotational kinetic energy
  • Principle of conservation of angular momentum.
  • Define torque?
  • Relation between torque and angular acceleration of a rigid body.
  • Numerical=4,5,6, of every chapter

fluid statistics

  • Define surface tension and surface energy and illustrate the relations between them.
  • states and explain stokes law and find the coefficient of viscosity off gi9ven liquid using of this law.
  • Equations of continueity and its appilication
  • Bernoulli’s equations and its application
  • Newton’s formula for viscosity of liquid

Periodic motion

  • Derive the expression of time period for vortical oscillation of a mass suspended ffrom coiled spring
  • illustrate the time period of simple pendulum
  • define SHM
  • numerical 5,6,7,8 precise of each chapter

Question of heat and thermodynamics

  • First law of thermodynamiscs
  • work done during adiabatics process
  • dorkdone during isothermalm process
  • PV diagram of adiabatic process
  • PV diagram of isothermal process
  • Prove: PV^(gamma)=constant
  • what is internal combination engine.
  • define heat en gine and its efficiency
  • illustrate carrot cycle with PV diagram
  • illustrate second law of thermodynamiscs
  • Numerical =4,5,6,7 of every chapter.

Question of wave and optics

  • Derivation of stationary and progressive wave
  • Difference between of stationary wave and progressive wave
  • laplace equation
  • dow does stationary wave formed (with figure)
  • y=a sin theta omega T
  • newtons formula of velocity of sound in gas
  • Resonance tube
  • Beat in formation
  • Open organ pipe
  • close organ pipe
  • End correction in pipe
  • Law of tranceverse wave in strings
  • drooler’s effect
  • Young’s double slit experiment
  • Huygens principle
  • Polarization/Brewster law
  • Diffraction through single slit

Question of Electricity and Magnetism

  • AC working principle
  • Kirchhoff’s law
  • find out the balanced condition of Wheatstone bridge using Kirchhoff’s law
  • shunt
  • combination of parallel and series resistors
  • define potentiometer and uses of it
  • conversion of galvanometer into ammeter or (voltmeter)
  • Biot savart law and its application
  • Amperes law and its application
  • joules law of heating
  • drift velocity and current velocity
  • choke coil
  • series circuit containing combination of resistance ,capacitance and inductance
  • seed beck effect and thermocouple
  • variation of resistance with thermometer
  • prove :E=Blvd
  • lenz law
  • Faraday’s law of electromagnetic induction
  • moving of galvanometer and its application
  • Tangent law and ferromagnetism
  • Relative permeability and susceptibility

Question of modern physics

  • Bohr’s postulates and find the energy of electron of nth orbit
  • Thomson’s experiment to calculate specific charge of an electron
  • Law of radioactive disintegration
  • Millikan’s oil drop experiment
  • Full wave rectifier
  • Gaseous discharge
  • Einstein’s photoelectric equations

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Most important numerical question from physics class 12

The speed of sound of frequency 200 Hz in air is 340ms^-1.calculate the wavelength of wave? Ans=170

A travelling wave in the positive x-direction has an amplitude 2 cm, frequency 75 Hz and velocity of propagation 45m/s . calculate the wave number ,the displacement of the particle velocity and particle acceleration at x=1.35 m from the origin at t=3 sec. Ans: wave number=1.66*10^-4 m,2*10^-2m,o ms^-1,4.5*10^3m/s^2

A source of sound frequency 550 Hz emits waves of wavelength 600nm in air at 20 degree Celsius. What is the speed of sound in air at this temperature? What would be wavelength of sound from the source in air at 0 degree Celsius? Ans=0.79m

A string of certain sonometer vibrates 100 times a second .its length is doubled and its tension altered until it make 150 vibration in a second. Find the ratio of new tension to the original. Ans=9:1

calculate the decibel increase if there is a two fold increase in the intensity of wave? Ans=3.01db

when a jet plane is flying on elevation 100m the sound level on the ground is 4.0 db. what would be the intensity level on the ground when its elevation is as low as 100m. Ans=24 db

in an experiment using young’s double slit ,the distance between Centre of the interference pattern and the tenth bright fringe on either side is 3.44 cm. distance between slit and the screen is 2 m. if the wavelength of the light used is 5.89*10^-7,determine the slit separation and angle made by the central bright fringe at the slit. Ans=3.42*10^-4m,3.4*10^-5 rad

Red light of wavelength 600 A from a distant source falls on a slit 0.50 nm wide .calculate the distance between the two dark bands on each side of central bright band of the different pattern observed on a screen placed 1.8m from the slit. Ans=4.66mm

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A plane transmission grating contains the slits 4000 lines per cm. Assume normal incidence. The alpha and bitaa lines emitted by automatic hydrogen have the wavelength 656 nm and 486 nm respectively. Compute the angular separation in degree between this lines in the record order spectrum. Ans=8.77 Degree

A galvanometer can bear a maximum current of 25 mA and has a resistance of 5 ohm. Find the suitable resistance to convert it into a. A voltmeter of range 0-2 V b. An ammeter of range 0-10 A Ans: R=80 ohms=0.0125 ohm

The wire of a fuse in an electric circuit melts when the current density increases to 600 A/cm^2.What should be the diameter of the wire so that it may limit the current to 0.4 A? Ans=0.29

A capacity of a storage battery ,such as those used in automobile electrical system rated in ampere-hours(A .h).A 50 A .h battery can supply a current of 50 A for 1.0h,or 25A for 2.0 h and so on .What total energy can be supplied by a 12V ,60A.h. batt4ery if its internal resistance is negligible? Ans=(a):0.2 ohm,(b)8.7V

find the emf of a cell which balances against a length of a potentiometer write .given political difference per cm of wire as 0.006V. Ans=1.08V

The temperature of the cold junction of the thermocouple is kept at 10 degree Celsius. The temperature of inversion is 560 degree Celsius. Find the neutral temperature. Ans=285 degree Celsius

if 1 mole if electron contains 6.02*10^23electrons,calculate the value of F.

A copper voltmeter and and ammeter are connected in series with a battery through a resistance .In 50 minujtes,0.99 g of copper is deposited on the plates. The ammeter reads 0.95 A. Calculate thee error in its reading .[e.c.e.of copper 0.00033 gC6^-1] Ans=0.05 A

A horizontal rod 0.200 m long is mounted on a balance and carries a current. At the location of the rod a uniform horizontal magnetic field has magnitude 0.067 T and direction perpendicular to the rod V .The magnetic force on the rod is measured by the balance and is found to be 0.13 N .What is the current? Ans=9.7 A

The total magnetic intensity at a place is 0.4 oersted and the single of dips is 30 degree .Calculate the horizontal and vertical components. Ans=0.43*10^-4 T,0.2*10^-4 T

A step down transforms ,a supply line voltage 220 volts into 100 volts. Primary coils has 50 turns .The efficiency and power transmitted by the transformer are 80% and 80 kW .Find (a)the numbers of turns in secondary coil;(b)power supplied Ans=Ns;227 ,Pin=10^5W

calculate the de Broglie wavelength of a particle of mass 2 kg moving with a velocity 5 m/s ? (h=6.62*10^-34Js) Ans=6.62*10^-35m

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The mass of 8O16 is 15.9949amu.calculate its binding energy. What is the binding energy per nucleon?(given Mn=1.008665 amu, Mp=1.007825 amu) Ans=127.54MeV,7.97 Mev/nucleon

An electron moves movies in a circular path of radius 20 cm in a uniform magnetic field of 2*10^-3 T .Find the speed of the electron and period of revolution. Mass of electron=9.1*10^-31kg. Ans=7.02*10^7m/sec and 5.56 *10 ^ 7 rev / sec

The isotope Ra-226 undergoes alpha decay with a half life of 1620years.Whataa is the activity of 1 g of Ra-226 ? Avogadro number=6.023*10^23/mole. Ans=3.47*10^10 dis / sec

Why physic is soo hard?

It is a very complex and complicated combination of computer science, mathematics, and basic science. Students have to learn and memorize countless laws and definitions. You also have to use concepts like geometry, algebra, and calculus to solve physics problems. Different types of numerical from different chapter makes difficulty this subject.

How to pass physics easily?

These are the following steps of pass physics easily.

  1. Take careful notes during each class or lecture, then review them shortly after.
  2. Take notes as you read textbook assignments.
  3. Regularly combine your class and textbook notes so, when you are readying for an exam, you have one comprehensive set of notes to work with.
  4. complete the all important derivation of physics.
  5. Numerical question play vital role to pass in physics.
  6. focus and remember all the experiment which you have done in your laboratories.
  7. you must know the all formula of physics ,which make easier to solve numerical problem

I hope all of the questions and all of the topics definitely helps you during the period of your exam. Keep doing handwork guys you will definitely get a better result. Best of luck for your exam. If you think this article helps you a little Bittle then kindly share this article towards your friends and help them during the exam period.

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