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Dual Nature of Radiation And Matter - Notes, Topics, Formulas, Books, FAQs

Dual Nature of Radiation And Matter - Notes, Topics, Formulas, Books, FAQs

Edited By Team Careers360 | Updated on May 04, 2022 06:25 PM IST

As the name suggests Dual Nature of Matter and Radiation chapter deals with the duality in the nature of matter, namely particle nature and a wave nature. Various experiments by various scientists were done to prove it. For example, light behaves both as a wave and as a particle. If you are observing phenomenon like the interference, diffraction or reflection, you will find that light behaves as a wave. However, if you are looking at phenomena like the photoelectric effect, you will find that light behaves as a particle. You must have heard about solar energy in your earlier classes and how it can be a good alternative to the non-renewable sources of energy. We can use solar energy as a source of electricity using solar panels. The solar panel has solar cells (semiconductors like Si and Ge) and when photons hit the solar cells the electrons get excited and due to their movement electric current is produced. So here we got to know that light constitutes of photons or in other words light contains particles which are a packet of energy.


But light does not only shows particle nature it also shows the wave nature and you will get to know about it by various experiments. I hope now you understand why this chapter’s name is Dual Nature of Matter and Radiation.

Dual Nature of Matter and Radiation is one of the most important chapters from modern physics while preparing for all competitive exam because it helps you to understand the dual nature of matter. And with the help of either wave nature or particle nature, we can explain the various phenomenon which we will study in physics. This is easy to understand and a high scoring topic. The Concept of Dual Nature of Matter and Radiation and other chapters of physics are mixed in miscellaneous questions which are asked in various competitive exams.

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Notes on the Dual Nature of Matter and Radiation

So we will discuss step by step about important topics from this chapter followed by an overview of this chapter. Then we will understand important formulas from this chapter. Remembering these formulas will increase your speed while question-solving.
Dual Nature of Matter and Radiation Topics

  • Dual nature of radiation,

  • photoelectric effect,

  • Hertz and Lenard's observations,

  • Einstein’s photoelectric equation,

  • Matter-wave: the wave nature of particles,

  • De Broglie relation, Davisson and Germer experiment.

Also read,

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Dual Nature of Matter and Radiation Overview

  • In this chapter, we will study the dual nature of matter which will be explained by Wave-particle duality postulates. According to this postulates, all particles exhibit both wave properties and particle properties.
  • Then we will study the particle nature of the light wave. For this, we will consider light as particle or light consist of photons.
  • Then we will study various characteristics of photons, like its mass, energy, momentum, etc. There are various scientific experiments which will explain the particle nature of light and Photoelectric Effect experiment is one of them.
  • In photoelectric Effect experiment, the emission of electrons (photoelectron) takes place when light strikes a surface. We will understand all the procedure and results of this experiment. We will understand various terminology regarding this experiment and how they depend on each other. And based on their dependence on each other we can get different results if we change the input quantity of experiments. Einstein's Photoelectric Equation gives the relation between input and output quantity of experiments. This experiment also follows the Conservation of energy.
  • After studying the particle nature of matter we will learn about the wave nature of matter. So we will learn about De - Broglie wave which is nothing but a wave associated with the moving material particles. To understand the wave nature of matter it is very important to study about its associated De - Broglie wavelength. So we will study various characteristics of De - Broglie wavelength. We will study how De - Broglie wavelength of matter depends on various factors like its mass, frequency of the wave, etc. With the help of formula, we can also calculate values of De - Broglie wavelength for particles like electron, Deuteron, Alpha particle, etc.
  • There are various scientific experiments like Davisson Germer Experiment, Frank Hertz Experiment, etc which will explain the wave nature of matter.

Dual Nature of Matter and Radiation Formulas

  1. The energy of a photon-

\fn_jvn E= h\nu = \frac{hc}{\lambda }

  1. Kinetic mass of the photon= m=\frac{E}{c^{2}}= \frac{h}{c\lambda }
  2. The momentum of photon= \fn_jvn P = \frac{E}{C}= \frac{h}{\lambda }
  3. work function-w= h\nu _{0}= \frac{hc}{\lambda _{0}}
  4. Einstein's Photoelectric Equation= h\nu =w+\frac{1}{2}mv^{2}_{max}

  5. De - Broglie wavelength- \lambda = \frac{h}{p}= \frac{h}{mv}= \frac{h}{\sqrt{2mE}}

NCERT Notes Subject Wise Link:

How to prepare Dual Nature of Matter and Radiation

  • First, you should have good command over the concepts of the Dual Nature of Matter and Radiation and you should also know how to apply them well at the time of the entrance exam or while solving questions.
  • Please try to understand each concept from this chapter, with the help of theory, questions with solutions and video lectures on each important concept. For each concept practice enough problems so that you have a thorough understanding of the concept.
  • Solve all the questions at home with proper concentration and try to do all calculation by yourself without seeing the solution first.
  • While solving questions of Photoelectric Effect first find out the relation between work function and the energy of the incident wave and then solve for the result.
  • Please have a thorough knowledge of Effect of intensity, potential, frequency on photoelectric current.
  • Remember all the formulas of calculating De - Broglie wavelength. This will help you while solving questions.

Dual Nature of Matter and Radiation Tips

  • Make a proper plan to prepare for this chapter and Stick to it.

dual nature

  • Study the concept first and then start solving questions. Don't go through question directly without knowing the concept.
  • Formulas from this chapter are very important from the point of view of competitive exam. So please remember them and solve lots of questions based on these formulas.
  • Solve previous year question of various exam from this chapter.
  • Use smart methods to solve questions.

Dual Nature of Matter and Radiation Books

For Dual Nature of Matter and Radiation, chapter concepts in NCERT are enough but you will have to practice lots of questions including previous year questions and you can follow other standard books available for competitive exam preparation like Concepts of Physics (H. C. Verma) and Understanding Physics by D. C. Pandey (Arihant Publications).

NCERT Solutions Subject wise link:

NCERT Exemplar Solutions Subject wise link:


Get answers from students and experts

 5 g of Na2SO4 was dissolved in x g of H2O. The change in freezing point was found to be 3.820C.  If Na2SO4 is 81.5% ionised, the value of x (Kf for water=1.860C kg mol−1) is approximately : (molar mass of S=32 g mol−1 and that of Na=23 g mol−1)
Option: 1  15 g
Option: 2  25 g
Option: 3  45 g
Option: 4  65 g  

 50 mL of 0.2 M ammonia solution is treated with 25 mL of 0.2 M HCl.  If pKb of ammonia solution is 4.75, the pH of the mixture will be :
Option: 1 3.75
Option: 2 4.75
Option: 3 8.25
Option: 4 9.25


What is A?

Option: 1


Option: 2


Option: 3


Option: 4


\mathrm{NaNO_{3}} when heated gives a white solid A and two gases B and C. B and C are two important atmospheric gases. What is A, B and C ?

Option: 1

\mathrm{A}: \mathrm{NaNO}_2 \mathrm{~B}: \mathrm{O}_2 \mathrm{C}: \mathrm{N}_2

Option: 2

A: \mathrm{Na}_2 \mathrm{OB}: \mathrm{O}_2 \mathrm{C}: \mathrm{N}_2

Option: 3

A: \mathrm{NaNO}_2 \mathrm{~B}: \mathrm{O}_2 \mathrm{C}: \mathrm{Cl}_2

Option: 4

\mathrm{A}: \mathrm{Na}_2 \mathrm{OB}: \mathrm{O}_2 \mathrm{C}: \mathrm{Cl}_2

C_1+2 C_2+3 C_3+\ldots .n C_n=

Option: 1


Option: 2

\text { n. } 2^n

Option: 3

\text { n. } 2^{n-1}

Option: 4

n \cdot 2^{n+1}


A capacitor is made of two square plates each of side 'a' making a very small angle \alpha between them, as shown in the figure. The capacitance will be close to : 
Option: 1 \frac{\epsilon _{0}a^{2}}{d}\left ( 1 - \frac{\alpha a }{4 d } \right )

Option: 2 \frac{\epsilon _{0}a^{2}}{d}\left ( 1 + \frac{\alpha a }{4 d } \right )

Option: 3 \frac{\epsilon _{0}a^{2}}{d}\left ( 1 - \frac{\alpha a }{2 d } \right )

Option: 4 \frac{\epsilon _{0}a^{2}}{d}\left ( 1 - \frac{3 \alpha a }{2 d } \right )

 Among the following compounds, the increasing order of their basic strength is
Option: 1  (I) < (II) < (IV) < (III)
Option: 2  (I) < (II) < (III) < (IV)
Option: 3  (II) < (I) < (IV) < (III)
Option: 4  (II) < (I) < (III) < (IV)

 An ideal gas undergoes a quasi static, reversible process in which its molar heat capacity C remains constant.  If during  this process the relation of pressure P and volume V is given by PVn=constant,  then n is given by (Here CP and CV are molar specific heat at constant pressure and constant volume, respectively)
Option: 1  n=\frac{C_{p}}{C_{v}}

Option: 2  n=\frac{C-C_{p}}{C-C_{v}}

Option: 3 n=\frac{C_{p}-C}{C-C_{v}}

Option: 4  n=\frac{C-C_{v}}{C-C_{p}}

As shown in the figure, a battery of emf \epsilon is connected to an inductor L and resistance R in series. The switch is closed at t = 0. The total charge that flows from the battery, between t = 0 and t = tc (tc is the time constant of the circuit ) is : 

Option: 1 \frac{\epsilon L }{R^{2}} \left ( 1 - \frac{1}{e} \right )
Option: 2 \frac{\epsilon L }{R^{2}}

Option: 3 \frac{\epsilon R }{eL^{2}}

Option: 4 \frac{\epsilon L }{eR^{2}}

As shown in the figure, a particle of mass 10 kg is placed at a point A. When the particle is slightly displaced to its right, it starts moving and reaches the point B. The speed  of the particle at B is x m/s. (Take g = 10 m/s2 ) The value of 'x' to the nearest is ___________.
Option: 1 10
Option: 2 20
Option: 3 40
Option: 4 15

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