# Class 12 Physics Most Important Questions for NEB Board Exam 2079 | New Course

Are you a student or a teacher of Class 12 ? Are you searching for **most** **important** **questions** of **Physics** ? If yes, you are at the right place. Here, in this post, you will get the **most important questions **of **Physics **of **Class 12** for better **board exam** preparation. Share it with the needy ones. Keep Studying, Keep Hustling. Thank You.

Here, we have the most important questions intelligently collected from each chapters of Physics of Class 12. To secure good marks, you need to go through these questions.

If you find it helpful, please share it with the needy ones. Keep Studying, Keep Hustling. Wishing you best of luck for your **board exam** preparation. Thank You.

**Unit 1: Mechanics**

**1. Rotational dynamics**

1.1. Recall equations of angular motion and compare them with equations of linear motion

1.2 Derive the expression for rotational kinetic energy

1.3 Describe the term moment of inertia and radius of gyration

1.4 Find the moment of inertia of thin uniform rod rotating about its center and its one end

1.5 Establish the relation between torque and angular acceleration of a rigid body

1.6 Describe the work and power in rotational motion with expression

1.7 Define angular momentum and prove the principle of conservation of angular momentum

1.8 Solve numerical problems and conceptual questions regarding the rotational dynamics

**2. Periodic motion**

2.1 Define simple harmonic motion and state its equation.

2.2 Derive the expressions for energy in simple harmonic motion

2.3 Derive the expression for period for vertical oscillation of a mass suspended from coiled spring

2.4 Describe angular simple harmonic motion and find its period

2.5 Derive expression for period of simple pendulum

2.6 Explain the damped oscillation

2.7 Describe forced oscillation and resonance with suitable examples

2.8 Solve the numerical problems and conceptual questions regarding the periodic motion

**3. Fluid statics**

3.1 State and explain Archimedes principle and Pascal's law

3.2 Define up-thrust, pressure in fluid, buoyancy, center of buoyancy and meta center

3.3 State and use the law of floatation,

3.4 Describe surface tension and explain its principle

3.5 Establish the relation between surface energy and surface tension

3.6 Define angle of contact and capillarity with examples

3.7 State the Newton's Formula for viscosity of a liquid and define coefficient of viscosity

3.8 Differentiate between laminar and turbulent flow & describe Reynolds number

3.9 Recall and use the Poiseuille's formula

3.10 State Stoke's law and use it to determine the coefficient of viscosity of given liquid

3.11 Explain equation of continuity and its application

3.12 Recall the Bernoulli's equation and explain its uses

3.13 Solve the numerical problems and conceptual questions regarding the fluid statics

**Unit 2 : Heat and Thermodynamics**

**4. First Law of Thermodynamics**

4.1 Clarify the concept of thermodynamic system.

4.2 Explain the meaning of work done by the system and work done on the system, and describe how work

done by gas during expansion can be calculated from indicator (P - V) diagram.

4.3 Explain the concept of latent heat and internal energy.

4.4 State and explain first law of thermodynamics - increase of internal energy (du) = heat into the system (dQ) + work done on the system (PdV) realizing its limitations and necessity of second law of thermodynamics.

4.5 Define and explain two specific heat capacities of gas appreciating the relation Cp - Cv = R and cp - cv = r.

4.6 Explain various thermodynamic process (isothermal, isobaric, isochoric and adiabatic) with good concept of their P - V diagram.

4.7 Derive adiabatic equation PV = constant.

4.8 Derive expression for work done during isothermal and adiabatic process.

4.9 Give concept of reversible and irreversible process with examples.

4.10 Solve mathematical problems related to first law of thermodynamics and thermodynamic process.

**5. Second Law of Thermodynamics**

5.1 State and explain second law of thermodynamics (Kelvin's and Clausius's statement).

5.2 Compare second and first law of thermodynamics considering indication of direction of flow of heat.

5.3 Explain heat engine as a device to convert heat energy into mechanical energy appreciating that its efficiency is less than 100%.

5.4 Discuss Carnot's cycle with the concept of P - V diagram and calculate the work done of each step and corresponding efficiency.

5.5 Describe internal combustion engines, Otto engine and diesel engine with the help of P - V diagram to compare their efficiencies.

5.6 Explain refrigerator as heat engine working in reverse direction

5.7 Introduce entropy as a measure of disorder appreciating its roles in thermodynamic process.

5.8 Solve mathematical problems related to heat engine.

**Unit 3: Wave and Optics**

**6. Wave motion**

6.1 Define and understand progressive wave

6.2 Write progressive wave in mathematical form

6.3 Discuss the condition under which stationary waves can be formed

6.4 Write stationary wave in mathematical form

6.5 Calculate frequency, amplitude, velocity, time period, etc of progressive wave 6.6 Find expression for stationary wave using two progressive waves

**7. Mechanical waves**

7.1 Calculate Speed of wave motion

7.2 Understand and write expression for the Velocity of sound in solid and liquid

7.3 Describe Velocity of sound in gas

7.4 Describe Laplace correction

7.5 Formulate the effect of temperature, pressure, humidity on velocity of sound and their physical meaning

7.6 Solve numerical problems related to velocity of sound in the given medium and condition

**8. Wave in pipes and strings**

8.1 Understand the formation of stationery waves in closed and open pipes

8.2 Define and understand harmonics and overtones

8.3 Discuss harmonics and overtones in closed and open organ pipes

8.4 Understand end correction in pipes

8.5 State and use the formula for velocity of transverse waves along a stretched string

8.6 Understand Vibration of string and overtones

8.7 Know the laws of vibration of fixed string

**9. Acoustic phenomena:**

9.1 Describe sound waves as pressure waves in a medium

9.2 Characterize the sound using its intensity, loudness, quality and pitch

9.3 Discuss Doppler's effect

9.4 Apply Doppler effect in realistic case where source and observers are in relative motion.

**10. Nature and propagation of Light:**

10.1 Use Huygen's principle to explain reflection and refraction of light

**11. Interference**

11.1 Explain the Phenomenon of Interferences

11.2 Understand the meaning of coherent sources

11.3 Describe Young's double slit experiment and obtain the expression fro nth order maxima

**12. Diffraction**

12.1 Describe diffraction at a single slit

12.2 Understand diffraction pattern of image and derive the expression for the position of nth order minima

12.3 Explain diffraction through transmission/diffraction grating and use the formula for maxima

12.4 Explain resolving power of optical instruments

**13. Polarization**

13.1 Describe phenomenon of polarization

13.2 Explain how polarization of light explains the transverse nature of light

13.3 State and use Brewster's law

13.4 Show the understanding of construction, working principle and uses of Potentiometer for comparing emfs and measuring internal resistance of cells

**Unit 4: Electricity and Magnetism**

**14. Electrical circuits:**

14.1 Understand Kirchhoff's law as well as use it to calculate unknown parameters in electrical circuits

14.2 Describe the circuit diagram and working of Wheatstone bridge circuit and understand its importance in real situation

14.3 Describe Meter bridge and understand it

14.4 Know construction, working and importance of Potentiometer

14.5 Understand the concept of super conductors

14.6 Know the meaning of perfect conductors and distinguish it from superconductor

14.7 Learn the technique to convert galvanometer into voltmeter and ammeter

**15. Thermoelectric effects:**

15.1 Explain Seebeck effect and its application in Thermocouples

15.2 Show understanding of the construction and working principle of thermocouple as a temperature measuring device

15.3 Explain Peltier effect

15.4 Understand the construction and working of Thermopile

**16. Magnetic field:**

16.1 Show understanding of the concept of magnetic field lines and magnetic flux and sketch magnetic field lines around a straight current carrying conductor and long solenoid

16.2 Explain Oersted's experiment, its outcome and limitations

16.3 Discuss force on moving charge in uniform magnetic field

16.4 Discuss force on a current carrying conductor placed in uniform magnetic field

16.5 Describe force and Torque on rectangular coil placed in uniform magnetic field

16.6 Describe moving coil galvanometer and know its applications

16.7 Explain Hall effect and derive the expression V_{H}=BI/ntq where t is thickness

16.8 Use Hall probe to measure flux density of a uniform magnetic field

16.9 State Biot and Savart law and know its application on (i) a circular coil (ii) a long straight conductor (iii) a long solenoid

16.10 State Ampere's law and know its applications to (i) a long straight conductor (ii) a straight solenoid (ii) a toroidal solenoid

16.11 Discuss force between two parallel conductors carrying current- definition of ampere

**17. Magnetic properties of materials:**

17.1 Define relative permeability and relative susceptibility of a magnetic material

17.2 Discuss relationship between relative permeability and susceptibility

17.3 Discuss Hysteresis of ferromagnetism

17.4 Understand Dia,-para- and ferromagnetic materials

**18. Electromagnetic Induction:**

18.1 State and show understanding of Faraday's law of electromagnetic induction

18.2 State and show understanding of Lenz's law

18.3 Discuss construction and working of A.C. generators

18.4 Define eddy currents, explain how they arise and give a few examples where eddy currents are useful and where they are nuisance

18.5 Describe self-inductance and mutual inductance and understand their uses

18.6 State the expression for energy stored in an inductor and use it wherever needed

18.7 Discuss the construction, working principle and importance of transformer

18.8 Discuss the sources of energy loss in practical transformer

**19. Alternating Currents:**

19.1 Understand peak and rms value of AC current and voltage

19.2 Discuss AC through a resistor, a capacitor and an inductor

19.3 Understand Phasor diagram in RC and RL circuits

19.4 Discuss series circuits containing combination of resistance, capacitance and inductance

19.5 Describe series resonance condition and know its applications

19.6 Understand the meaning of quality factor

19.7 Discuss power in AC circuits and know the term power factor

**Unit 5: Modern Physics**

**20. Electrons**

20.1 Describe Millikan's oil drop experiment and explain how it suggests quantization of charge

20.2 Describe the motion of electrons in electric and magnetic fields and derive appropriate mathematical expressions

20.3 Describe J.J Thomson's experiment with suitable diagrams to explain the discovery of electron and its characters

20.4 Solve numerical problems related to above topics

**21. Photons**

21.1 Describe quantum nature of radiation

21.2 Explain properties of photons

21.3 Describe work function and photoelectric effect

21.4 Derive Einstein's photoelectric equation

21.5 Describe Millikan's experiment for the verification of Einstein's photoelectric equation and calculate Planck's constant

21.6 Solve some related problems

**22. Semiconductor devices**

22.1 Describe the formation of PN junction and semiconductor diode

22.2 Plot forward and reverse characteristics of semiconductor diode including the concept of Zener diode

22.3 Define rectifier

22.4 Describe full wave rectification using semiconductor diodes

22.5 Define logic gates and explain operation of different logic gates OR, AND, NOT, NAND and NOR gates with their symbol, Boolean algebra and truth table

**23. Quantization of energy**

23.1 Write the postulates of Bohr's model

23.2 Derive the expression of radius of nth orbit, velocity of electron in nth orbit and total energy of electron in nth orbit of H-atom

23.3 Obtain the expression of wavelength of a spectral line

23.4 Obtain mathematical expressions different spectral series of H-atom

23.5 Differentiate excitation and ionization potentials

23.6 Explain emission and absorption spectra

23.7 Describe de Broglie hypothesis

23.8 Define x-rays

23.9 Describe modern Coolidge tube method for the production of x-rays with quality and quantity

23.10 Illustrate different properties of x-rays along with their applications

23.11 Solve numerical problems related to quantization of energy

**24. Radioactivity and nuclear reaction**

24.1 Explain the meaning of Radioactivity - natural and artificial

24.2 Differentiate types of radiations coming from radioactive sources - alpha, beta particles and gamma rays and state their properties

24.3 Explain radioactive disintegration law

24.4 Obtain the expressions of half-life, decay constant and mean life

24.5 Explain the working of Geiger-Muller Tube

24.6 Analyze some medical uses and health hazard of nuclear radiation

24.7 Work out some related numerical problems

24.8 Reason conceptual questions

**25. Recent trends in physics**

25.1 Seismology

a. Briefly explain the origin of earthquakes

b. Explain different types of surface waves: Rayleigh and Love waves

c. Explain different types of internal waves: S and P-waves

d. Give brief introduction to the wave patterns of Gorkha Earthquake 2015 25.2 Demonstrate basic ideas on

a. Gravitational Wave

b. Nanotechnology