## Class 12 Physics Important Question

This article contains **91 important questions** of Class 12 Physics based on the revised syllabus of NEB Exam 2079 & 2080.

These are important physics questions for class 12 neb electricity and magnetism section.

We all find electricity and magnetism chapter tough as it is more technical than other chapters, but if you practice, study or remember everything listed here, you will be able to do well in this section too.

Physics Important Question for NEB Examination |

The most **important Class 12 Physics questions** for the NEB Exam 2023 are listed here:

Define wave motion. Derive the progressive wave equations in a medium.

Starting with the definition of stationary waves, prove that the distance between any two consecutive nodes or antinodes in a stationary wave is ƛ/2.

Write an expression for Newton's formula for the velocity of sound in air. Explain the necessary correction made by Laplace.

Define end correction. Show that, in an open organ pipe, both odd and even harmonics can be produced.

Define natural frequency. Describe an experiment to determine the velocity of sound in air by the resonance air column tube method.

Describe a sound wave as a pressure wave and deduce an expression for the pressure amplitude.

Define beats. Obtain an expression for the beat frequency produced by the superposition of two waves of slightly different frequencies.

What is the Doppler effect in sound? Obtain an expression for the apparent frequency of sound when both source and observer are moving towards each other.

State Huygens law and use it to verify Snell's law.

Define coherent sources of light. Describe Young's double-slit experiment and show that the bright fringes and dark fringes are equally spaced.

Define polarization of light. Show that, μ=tan𝜭p, where the symbols have their usual meanings.

How can you convert a galvanometer into an ammeter (or voltmeter)? Explain.

Discuss the mechanism of metallic conduction. Derive a relation between current density and drift velocity.

State and apply Kirchhoff's rule to measure the unknown resistance of a wire by using the Wheatstone bridge circuit.

State the principle of meter bridge. Describe how it is used to determine the resistance of a wire.

What is the principle of a potentiometer? Explain with necessary theory how you would determine the internal resistance of a cell using this principle.

What do you mean by the thermoelectric effect? Discuss the variation of thermo emf in a thermocouple with the temperature change.

State and explain Biot - Savart's law. Use it to find the magnetic field due to a long straight current-carrying conductor.

State Ampere's law. Deduce an expression for the force between two parallel current-carrying wires.

State Faraday's law of electromagnetic induction. Derive an expression for the emf induced in a straight conductor moving at right angles to the direction of a uniform magnetic field.

State Faraday's law of electromagnetic induction. Deduce an expression for the emf induced in a coil rotating uniformly in a uniform magnetic field.

Explain the principle and working of a transformer.

Discuss the condition for the resonant frequency of the LCR alternating current circuit.

Describe the construction and working principle of Millikan's oil-drop experiment to determine the charge of an electron.

Define cross-field. Describe the construction and working principle of J.J. Thomson's experiment to determine the specific charge of an electron.

Define the threshold frequency and work function of a metal. Explain Einstein's photoelectric equation.

Describe the experiment to determine Planck's constant.

State Bohr's postulates for the atomic model. Derive the expression for the radius of an electron bound to a hydrogen atom. (OR, to find the total energy of an electron in nth orbit.)

Explain Bragg's law of diffraction for X - rays.

What is Zener's breakdown? How can a Zener diode be used as a voltage regulator? Explain.

Define mass defect. Explain the significance of the graph of binding energy per nucleon versus the atomic mass number.

State the laws of radioactivity. Derive the relation between the half-life period and decay constant.

Equation of Progressive wave

Wave front and Wavelets: Clear Concepts with Difference

Newton's formula with Laplace's Correction

Light wave and Sound wave with Difference

Stationary wave equation

Laws of transverse vibration in stretched strings

Open Organ Pipe and Close Organ Pipe

Doppler Effect

Pressure amplitude

Reflection and refraction using Huygens Principle

Polarization for Short Question

Young's Double Slit Experiment

Diffraction through single slit

Diffraction grating numerical

Meter bridge

Kirchhoff's law and numerical

Wheat stone bridge principle

Principle of Potentiometer and numerical

Conversion of galvanometer into voltmeter and ammeter

Joule's law

Seebeck experiment

Peltier and Thomson effect

Biot and Savart Law and its applications

Ampere Circuital law for Derivation and Numerical

Hall effect and Moving coil galvanometer

What is Eddy Current? Write down its uses.

LR, RC, LCR series circuit with wave diagram and Phasor diagram and Numerical

Resonant frequency, Power factor and Quality factor

Theory and working of AC generatorFaraday's Laws of Electromagnetic Induction

Motional emf derivation and Lenz law

Only Numerical of Induced emf in rotating rod (wheel spokes) and wings of airplane

Energy stored in an inductor and Transformer derivation

Millikan's Oil drop experiment

JJ Thomson Experiment

Motion of electron in Electric Field and Magnetic Field for Numerical

Energy of hydrogen orbit

Stopping Potential and Threshold Frequency

X ray and its application

P type, N type Semi conductor, PN Junction, Logic Gates concept

Nanotechnology definition

Semiconductor Diode (Forward and Reverse Bias)

Full wave Rectifier

Simple pendulum

Bragg's Law

GM counter

Laws of Radioactivity (Half life, mean life and decay constant) and Numerical

Spring motion and its time period

Moment of inertia of geometrical shapes

Principle of conservation of angular momentum and numerical

Archimedes principle and law of floatation numerical

Surface energy and surface tension

Surface tension by capillary action and numerical

Stokes law and numerical

Bernoulli principle and application

Mayer's relation

Adiabatic gas equation and Work done In Adiabatic and Isothermal process.

Petrol and Diesel engine

Surface waves, Rayleigh and love waves, S and P-waves.

Principle of conservation of angular momentum

As a conclusion, these are the most important NEB final exam questions.

Practice all of these questions in order to get full marks on your upcoming exam.

**Read:** Important Topics Class 12 Physics

These questions have been asked over the years, so they are important.

Don't stress because the questions in NEB board exam are simple.

Above mentioned concepts are also important in our other exams like IOE, IOM, BSC CSIT. Those who want to prepare for such higher level exams can study these concepts in details.

Finally, we advise everyone to prepare for the upcoming NEB exam.

Goodbye for the time being.

**All the best for your upcoming exams **

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