(c) Why should gases be insulators at ordinary pressures and start conducting at very low pressures? At the beginning of the twentieth century, scientists unravelled one of the best-kept secrets of nature – the wave particle duality or the dual nature of matter and radiation. Here, v = frequency, λ = wavelength, c = speed of light, and h = Planck’s constant. Radiation falling on the metal surface provided free electrons enough energy to neutralize the attractive force of positive ions and escape themetal surface to intensify the sparks across the metal loop. If each of these metals is exposed to radiations of wavelength 3300nm, which of these will not exit photoelectrons and why? 6.Show graphically how the stopping potential for a given photosensitive surface varies with the frequency of incident radiations? : X-rays can cause damage to the tissues of body (cells are ionized and molecules are broken). To derive the Compton shift. Ans. Wave–particle duality postulates that all particles exhibit both wave and particle properties. 5.Ultraviolet light is incident on two photosensitive materials having work function and  ( > ). This electron is completely stopped and will emit the photon of highest energy. (Photoelectric effect), Fig. For threshold frequency, the relation for kinetic energy is written as: Therefore, the threshold frequency for the photoemission of electrons is s. 3. Hg, are called cathode rays. Total number of photons may or may not be constant. Give reason for your answer? Germer (1896-1971). (b) we consider a single drop of mass m, radius r carrying a negative charge –q in the presence of electric field acting downward. The relation for the de Broglie wavelength is given as: Therefore, the de Broglie wavelength of the neutron is 0.146 nm. No photoelectrons are emitted, if the frequency of incident light is less than some. This least value of energy is called work function of metal (denoted by Φ, Work function of a material depends mainly on the nature of metal, and electronic configuration of metal (meaning the number of valence shell electrons, lesser the number, lesser the work function), Thermionic emission is the process in which thermal energy is used to overcome the work function of metal in order to force out the free electrons from the metal surface. It can be observed that the obtained curve is a straight line. The power emitted is 9.42 mW. Determine e/m from the data. - Mukul Sharma, IIT JEE One-year Classroom Program 2019, - Arpit Jain, IIT JEE Two-year Classroom Program 2020, - Taniya, NEET One-year Classroom Program 2019, - Ishani, NEET One-year Classroom Program 2019. The given quantities can be listed in tabular form as: The following figure shows a graph between . 1.Monochromatic light of wavelength 632.8 nm is produced by a helium-neon laser. Click here. Ans.Photoelectric cut-off voltage, = 1.5 V. The maximum kinetic energy of the emitted photoelectrons is given as: Therefore, the maximum kinetic energy of the photoelectrons emitted in the given experiment is J. But, alkali metals like sodium potassium etc. Interference, diffraction etc. could also absorb visible radiation to emit electrons, and so they were called photosensitive materials. Why do we not simply talk of e and m separately? (b) From your answer to (a), guess what order of accelerating voltage (for electrons) is required in such a tube? The experimental setup for the experiment is shown below: Evacuated chamberfor the free movement of electron without any air resistance, BatteryUsed for the acceleration of electrons inside the cylinder. Hence define threshold frequency? De Broglie’s wavelength for matter wave is given by: This principle was in favor of the wave nature of matter. 9. MCQ on Dual Nature of Matter and Radiation. Due to the presence of the other electrons. (c) At atmospheric pressure, the ions of gases have no chance of reaching their respective electrons because of collision and recombination with other gas molecules. So, photoelectric current gets doubled. In an experiment of photoelectric effect, the frequency () of incident light was tripled. (corresponding to energy maximum) = hc/Ve where V is the voltage applied. Determine the de Broglie wavelength associated with the electrons. (a) Quarks inside protons and neutrons are thought to carry fractional charges [(+2/3)e; ( – 1/3)e]. Deflected by electric and magnetic fields, Produce highly penetrating secondary radiation when suddenly stopped, In fig. Exercise: (Dual Nature Of Radiation And Matter) In an experiment of photoelectric effect, the … Experimental observation and studies of spectra of X-rays reveal that X-rays are of two types and so are their respective spectras. It proved that Photoelectric current, which is number of photoelectrons flowing per unit time, is directly proportional to the intensity of incident light, As the positive potential of collector rises, photoelectric current rises for a certain period of time because the electrons emitted experience a strong attractive force by the collector. At the peak, the probability of maximum number of electrons producing radiation. Threshold frequency depends on the nature of material used as an emitter. (b) What is so special about the combination e/m? However, the photoelectrons emitted from Na and K will increase in proportion to intensity. The phenomenon is called fluorescence. Case-2-When collector plate was kept at lower potential (retarding potential) with respect to the emitter. Hertz, in 1887 discovered the phenomena of photoelectric effect for the first time, As he was experimenting on the generation of electromagnetic waves by spark discharge, he noticed that sparks around the detector loop were intensified when ultraviolet radiation fell on the emitter plate. He found that K, radiation of different elements were different, where a and b depend on the particular line of the radiation, where R = Rydberg constant and c = speed of light, In general the wavelength of K - lines are given as, X-rays are absorbed by the materials according to the relation I = I, , where μ is absorption coefficient and x is the thickness of the material. The kinetic energy of the neutron is given by the relation: De-Broglie wavelength of the neutron is given as: It is clear that wavelength is inversely proportional to the square root of mass. 3.The maximum kinetic energy of photoelectron is 2.8 eV. Prepare yourself for IIT JEE Advanced with intensive guidance imparted by seasoned mentors. Ans.Wavelength of ultraviolet light, = 2271 ¦ =, Stopping potential of the metal, V0= 1.3 V. We have the photo-energy relation from the photoelectric effect as: Let  be the threshold frequency of the metal. Ans. But if V is equal to V, (i.e., cut off. Dual Nature of Radiation and Matter is chapter 11 of NCERT textbook for CBSE class 12. Class 12 Physics Dual Nature Radiation Matter: Introduction: Introduction: Do radiations have properties resembling a wave, a particle, or both? GATE. How does the stopping potential applied to a photocell change if the distance between the light source and the cathode of the cell is doubled? This was the third inconsistency with the experiments. Cylinder with fine hole along its axisconnected to the battery so that electrons entering it could be accelerated to high speed. If light of frequency Hz is incident on the metal, predict the cutoff voltage for the photoelectric emission. (a) Define photoelectric work function? What is the radius of the circle traced by the beam, given e/m for electron equals. Let n be the number of photons emitted by the transmitter. (a) Wavelength produced by an X-ray tube. This minimum value of frequency of incident light required for photoelectric emission to take place was called as threshold frequency, The value of threshold frequency is fixed for a specific material, and it changes from one material to another, Photoelectric current is directly proportional to the intensity of incident light, Saturation current increases if intensity of radiation increases, Stopping potential doesn’t depend on the intensity of light, Sopping potential, and maximum kinetic energy of photoelectrons, are linearly related to the frequency of incident light, For every material, there is a minimum value of frequency (threshold frequency) of incident light required for photoelectric emission to take place, below which no photoelectric effect occurs. 2. The modern apparatus for the production of X-rays was developed by Dr. Coolidge in 1913. 9. Here came the second inconsistency of wave theory with the experimental results. There are certain substances which continue emitting light for some time after the light incident on them is stopped. (ii) Stopping potential does not depend on the intensity of incident radiations. Ans. Mr.Sangram Patro PGT Physics.Students are advised to watch the class very attentively and participate on Quiz and Home assignments. (c) maximum speed of the emitted photoelectrons? emitted electrons only by absorbing ultraviolet light. The photoelectric effect proves the particle nature of radiation. Dual Nature of Radiation and Matter Class 12 Physics Revision Notes cover the following topics for your board exam. Ans.Mo and Ni will not show photoelectric emission in both cases. 18.Ultraviolet light of wavelength 2271 ¦ from a 100 W mercury source irradiates a photo-cell made of molybdenum metal. It is inconsistent with the wave theory of light, which predicts that photoelectric effect occurs at any frequency provided intensity of incident light is sufficiently high. (a) Power of the medium wave transmitter, P= 10 kW = 104 W = 104J/s, Hence, energy emitted by the transmitter per second, E= 104. Then by free body diagram (fig. But de-broglie wavelength of an electron is given by. . This proved the universal nature of cathode ray particles. The scattered x-rays has less energy than the incident x-rays. The excess energy is taken by recoiling electrons. How would the photo-cell respond to a high intensity  red light of wavelength 6328 ¦ produced by a He-Ne laser? 9. Find the change in the following: a) Saturation current (i), and b) work function of metal. Given, Φo = 2.14eV = 2.14×10-19J, and ν = 6×1014Hz. Hg – cathode glow, Crooke’s dark space, negative glow, Faraday’s dark space and striations are observed. Ans. Save my name, email, and website in this browser for the next time I comment. They are not deflected by electric or magnetic field. (b) The energy of a photon is given by the relation: Therefore, the energy of the photon is 1.243 keV. : The X-rays of longer wavelength are called soft X-rays. It is denoted by (V, Mathematically, stopping potential could be expressed as. They are not free to move out of the metal. Previous Year Papers. 9, Laxmi Nagar Delhi-110092. Ans.The wavelength of a wave associated with a moving football is extremely small, which cannot be detected. (a) For what kinetic energy of a neutron will the associated de Broglie wavelength be? In 1897, he termed this negatively charged cathode ray particles as electron, and this name was used for the first time. Colour is yellowish-green for soda glass and greyish-blue for lead glass. a) Using Einstein’s photoelectric equation: Kmax = hv – Φo = (6.6×10-34×6×1014)J – (2.14×10-19)J. b) Stopping potential is given by the equation: c) Maximum speed of emitted electrons can be found using maximum kinetic energy equation: 2)Question:  Light of wavelength 488nm is incident on an emitter plate. 11. When the values of photoelectric current were plotted against the different values for intensity of light, it was observed to be a straight line passing through the origin. Surface area of a sodium photocell, A=  =, Number of layers of sodium that absorbs the incident energy, n= 5. Work function of Na is 2.3eV. Electrons are collected at anode A, constituting a current in the circuit. Speed of the bullet, v= 1.0 km/s = 1000 m/s. The specific charge of the electron, i.e., its e/m is given to be C. (b) Use the same formula you employ in (a) to obtain electron speed for an collector potential of 10 MV. This frequency is called threshold frequency. 12. According to De Broglie’s hypothesis, matter wave is given by: On putting the value of V= 55V (the value at which a strong peak was detected), we get. This proved that electrons are released from the metal surface when ultraviolet radiation is incident on it, They also observed that electrons are not emitted when the frequency of light incident is less than a specific least value, called the threshold frequency. Hence, this experiment proved that electron behaves as a wave under specific conditions. It also is a spectrum consisting of radio waves, microwaves, infrared waves, visible light, ultraviolet radiation, X-rays, and gamma rays. It is difficult to remove a free electron from copper than from sodium? Here I is the intensity after penetrating the material through distance x and I, The coefficient of absorption (μ) of the material is given by. Mathematically, if   p = fixed  , Then, Δp→0, Δx→∞. It is clear from fig. potential), no electrons will reach the anode, i.e., Maximum kinetic energy of electron = eV, where e is charge of electron (e = 1.6 × 10. X-rays are produced when fast moving electrons are suddenly stopped on a metal of high atomic number. Get the Solomon's key to qualifying CBSE NEET exams with the expert guidance of seasoned mentors. The characteristic line spectra is superimposed on a continuous X-rays spectra of varying intensities. Hence, the wave picture is in disagreement with the given experiment. Taking Max Planck assumptions, Einstein postulated that a beam of light consists of small packets of energy called, . Notes 301 Dual Nature of Radiation and Matter PHYSICS MODULE - 7 Atoms and Nuclei z state the laws of photoelectric emission; z interpret the graphs between frequency of radiation and retarding potential; z write deBroglie wavelength of matter waves associated with a particle of momentum p ; and z describe the experimental arrangement for the verification of matter waves. 15. What is the de Broglie wavelength of a nitrogen molecule in air at 300 K? 1.The following table gives the values of work functions for a few sensitive metals. (c) a dust particle of mass kg drifting with a speed of 2.2 m/s? de-Broglie wave is not an electromagnetic wave but the matter wave. For the production of stationary waves in the orbit the circumference of the orbit should be integral multiple of wavelength of waves associated with the electron, Further experimental proof for photon concept (i.e., particle nature of light) was discovered in 1923 by American Physicist, A.H. Compton. Free electrons in a metal are free in the sense that they move inside the metal in a constant potential (This is only an approximation). When an electron is missing in the ‘K’ shell, an electron from next upper shell makes a quantum jump to fill the vacancy in ‘K’ shell. When light of frequency Hz is incident on the metal surface, photoemission of electrons occurs. In the above formula, the expression for energy can only be used in the non-relativistic limit, i.e., for v << c. When very high speeds are concerned, the relativistic domain comes into consideration. 23.Crystal diffraction experiments can be performed using X-rays, or electrons accelerated through appropriate voltage. Ans. Since, the photocell will not respond to the red light produced by the laser. 27. Electronic Devices. At low pressures, ions have a chance of reaching their respective electrodes and constitute a current. de-Broglie wavelength associated with electron accelerated under a potential difference V volt is given by. Do radiations have properties resembling a wave, a particle, or both? Dual Nature of Radiation and Matter; 1 (current) 2; 3; 4; The de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (Kelvin) and mass m, is (a) h m k T (b) h 3 m k T Diffraction maximum of electrons accelerated with 54 volt is obtained at θ = 50º for the Nickel crystal. Thus, the resolving power of an electron microscope is nearly 105times that of an optical microscope. ], Magnetic field experienced by the electron, B=. (d) The work function of a metal is the minimum energy required for a conduction electron to get out of the metal surface. Photoelectric emission is the process where free electrons are removed from a metal surface using a light of certain frequency on that metal. The momentum of a proton or a neutron is given as: The relativistic relation for energy (E) is given as: Thus, the electron energy emitted from the accelerator at Stanford, USA might be of the order of 1.24 BeV. Photoelectric work function of a metal is 1eV. Ammeter to measure the value of photoelectric current. If the source of light is brought near the photocells and placed 50 cm away from them, then the intensity of radiation will increase. This is because the mass of a microscopic object is very small, so wavelength becomes sufficiently large andhence, observable. In an experiment of photoelectric effect, the intensity () was doubled. Find the change in the following:a) Photoelectric current (i), b) Stopping potential (Vo), and c) maximum kinetic (Kmax) energy of the photoelectrons. These relations give the value of velocity of an electron as and. Therefore, the product (phase speed) has no physical significance. Ignore the small initial speeds of the electrons. Calcium sulfide and barium sulphide, after absorbing sunlight, produce blue phosphorescence for some time. This does not affect the energy of the radiation. ], Mean separation between two electrons, r=. prove wave nature of radiations. Dear Students, This uniquely designed Physics course on DUAL NATURE OF RADIATION AND MATTER is dedicated to the students of Class XII Under the DAV Institutions Odisha Zone-1. An  and a proton are accelerated from rest through same potential difference V. find the ratio of de–broglie wavelength associated with them? Since wave theory could not explain the photoelectric effect, Einstein proposed a particle theory of light for the first time, He said that radiations are made up of specific and discrete packets of energy called as quanta of radiation energy. 11. Where hc/λ is energy of scattered X-rays, K, is kinetic energy of recoiling electron & hc/λ, is the energy of incoming X-rays. If an electron beam of energy eV (electron volts) is incident on the target material; the electrons are suddenly stopped. … Ans. And the electrons released due to photoelectric effect are called photoelectrons, Evacuated tube consist of photosensitive plate (emitter) and the metal plate (collector), so that electrons could freely flow from emitter to collector without any air resistance, Photosensitive plate (emitter) to absorb visible light and emit electrons, Metal plate (collector) to receive electrons emitted from the emitter, thus constituting a photoelectric current flow from collector plate to the emitter plate (opposite to the flow of electrons), Monochromatic light of short wavelength (meaning high frequency), Battery to accelerate emitted electrons through a potential difference, Voltmeter to measure the potential difference between the emitter and the collector plates due to photoelectric current flow. It is given in the previous problem that the inter-atomic spacing of a crystal is about , i.e., . It intersects the at Hz, which is the threshold frequency  of the material. 25.An electron microscope uses electrons accelerated by a voltage of 50 kV. Hence, these emitted electrons show different energy distributions. Work Function (φ) of Some Elements Given in Brackets : (Quantum theory of light) we can explain above failures of classical physics. (a) maximum kinetic energy of the emitted electrons. All the electrons in an atom do not have the same energy level. When quinine sulphate is illuminated with ultraviolet or violet light it gives out blue light. The potential at which this happens is called sparking potential. 26.The wavelength of a probe is roughly a measure of the size of a structure that it can probe in some detail. (a) The minimum amount of energy required to take out an electron from the surface of metal. The second number tells you why our eye can never ‘count photons’, even in barely detectable light. Dual nature of radiation: Wave theory of electromagnetic radiation explains the phenomenon of interference, diffraction, and polarisation. Photoelectrons are emitted with a maximum speed of 7105m/s from a surface when light of frequency 81014Hz is incident on it. Electrons with a maximum speed of m/s are ejected from the surface. The transitions of electrons from various outer shells to the innermost ‘K’ shell produces a group of X-rays lines called as K-series. 8. Click here. [Note: Exercises 11.20(b) and 11.21(b) take you to relativistic mechanics which is beyond the scope of this book. Hence, wavelength  is significant, but the frequency  associated with an electron has no direct physical significance. Ans.Wavelength of the monochromatic radiation,  = 640.2 nm, Stopping potential of the neon lamp,  = 0.54 V. Let be the work function and  be the frequency of emitted light. They have been inserted here simply to emphasise the point that the formulas you use in part (a) of the exercises are not valid at very high speeds or energies. Dual nature of radiation Previous JEE Mains Papers questions and solutions Download Pdf Hence, the high-energy neutron beam should first be the rmalised, before using it for diffraction. X-rays are electromagnetic waves. (b) minimum wavelength of X-rays produced by 30 kV electrons. [Note: You will notice that to get h from the data, you will need to know e (which you can take to be ). Debroglie wavelength associated with an electron associated through a potential difference V is? Light of wavelength  falls on it. There are 3 types of electron emission; a) thermionic emission, b) field emission, and c) photoelectric emission. keyboard_arrow_down. . 5. Hence, gases are insulators at atmospheric pressure. If the frequency is halved and intensity is doubled, the photocurrent becomes (a) doubled (b) quadrupled … Physicswallah Assignment. Question 52. 5. This result is incorrect because nothing can move faster than light. A central concept of quantum mechanics, this duality addresses the inability of classical concepts like "particle" and "wave" to fully describe the behavior of quantum-scale objects. is the distance after traversing which the intensity of X-rays is reduced to half. This in distinguish ability has many fundamental implications which you will explore in more advanced Physics courses. is independent of intensity of incident light, but it depends on the frequency of incident light i.e., K. Electrons are emitted almost instantaneously consistent with particle view of light in which incident energy is concentrated in small packets (called photons) rather than over a large area (as in wave theory). Apply quantum ideas for understanding the operation and working principle of optoelectronic devices. It is clear from eq. Communication Systems ( All ) Select Topic. An electron has kinetic energy equal to 100eV. It was also found that, after reaching a certain minimum frequency value, stopping potential followed a linear relationship with the frequency of incident light. What is its unit? and wavelength of such radiation is continuous because the loss in energy is statistical. The wavelength of the sodium light is 589 nm. Lect 02: Photoelectric Effect-02. De Broglie wavelength is given by the relation: This wavelength is nearly 105 times less than the wavelength of yellow light. As the electrons lose energy by collision, longer wavelengths are produced the shape of the curve is statistical. The resolving power of a microscope is inversely proportional to the wavelength of light used. Question (1) based on dual nature of radiation (00:09) Question (2) based on dual nature of radiation (03:10) Question (3) based on dual nature of radiation (05:14) Question (4) based on dual nature of radiation (07:02) Answer: V=30kV = 30×10 3 V are taken to be roughly the same, how does the resolving power of an electron microscope compare with that of an optical microscope which uses yellow light? 4. Photoelectric emission is an instantaneous process, meaning there is no time lag between the incident light and the emission of free electrons (photoelectrons). Atoms ( All ) Select Topic. It is clear from expression (7) that Compton shift Δλ depends on scattering angle θ & not on the wavelength. The energy of the electrons is given by the relation: Hence, the maximum frequency of X-rays produced isHz. will be more for second surface whose work function is less. When an electron is accelerated through a potential difference V then the energy acquired by electron, When these high energy electrons fall on target T of high atomic number, then X-rays are produced, whose wavelength is given by, The shortest wavelength of X-rays emitted is. Calculate: a) momentum, b) speed, and c) De Broglie wavelength of the electron. GATE ECE Network Theory Control Systems Electronic Devices and Vlsi Analog Circuits Digital Circuits Microprocessors Signals and Systems Communications Electromagnetics Thus resulting in the emission of series of spectral line. In photoelectric effect all photoelectrons do not have same kinetic energy. Work function for copper is greater and it becomes difficult to remove a free electron from copper. As per the wave theory, the maximum kinetic energy of the photoelectron should be affected by the change in intensity. The photons. If V is the accelerating voltage applied then : If E is the energy of the particle, then. a) From the experiments on photoelectric effect, we know that :  i is directly propertion to I. A magnetic field of T curves the path of the electrons in a circular orbit of radius 12.0 cm. 7. prove wave nature of radiations. One important feature of continuous X-rays is that they end abruptly at a certain lower wavelength for a given voltage. They have higher penetrating power. 3. W is the threshold energy or work function depends upon threshold frequency. Experiments of this kind on Na, Li, K, etc. The quark structure of protons and neutrons appears at the minute length-scale of 10-15m or less. Wavelength of the emitted sodium light, = 589 nmm. : The X-rays of high frequency or low wavelength are said to be hard X-rays. Photoelectric Effect The phenomenon of emission of photoelectron from the surface of metal, when a light beam of suitable frequency is incident on it, is called photoelectric effect. Ans.Wavelength of light produced by the argon laser, = 488 nm, Stopping potential of the photoelectrons, = 0.38 V. From Einstein’s photoelectric effect, we have the relation involving the work function of the material of the emitter as: Therefore, the material with which the emitter is made has the work function of 2.16 eV. It stated that it is impossible to simultaneously evaluate the precise position and momentum of particle. They directed a beam of electrons at a crystal and observed that the electrons scattered in various directions for a given crystal orientation. (), Therefore, the wavelength associated with each -ray is. Therefore, the radius of the circular path is 22.7 cm. 16.In an accelerator experiment on high-energy collisions of electrons with positrons, a certain event is interpreted as annihilation of an electron-positron pair of total energy 10.2 BeV into two  rays of equal energy. Δλ, we apply both conservation of energy & momentum. On further absorption of ultraviolet radiation, neutral zinc plate became negatively charged. Hey, I'm Rajan.I'm determined to make your exam score grow.Lets start the free course. System of particles and Rotational Motion, Semiconductor Electronics : Materials, Devices and Simple Circuits, Please fill in the details for Personalised Counseling by Experts, Not found any post match with your request, Can not copy the codes / texts, please press [CTRL]+[C] (or CMD+C with Mac) to copy, Join IIT JEE & NEET Online Courses at CLEAR EXAM. An electron and an alpha particle have the same debroglie wavelength associated with them? Process, meaning a radiation possesses wave-particle dualism km/s = 1000 m/s emitted electron, B= seen in 11.31. Red light produced by an X-ray photon is given by: this wavelength is much than. Matter dual nature of radiation notes, your email address will not exit photoelectrons and?... We are going to discuss in this experiment the Pattern formed by the relation for the line and! Microscope uses electrons dual nature of radiation with 54 volt is given to be constant to! As electron, Ek= 120 eV ions have a wavelength λ plotting the above equation graphically we... A current come out with the frequency of incident radiation and nature of Matter- de Broglie wavelength of electron. For Every metal, cut-off voltage in a circular orbit r= 12.0 cm scientists were done to prove it )... Be constant get the Solomon 's key to qualifying CBSE NEET exams with decrease. Which is used in gold leaf electroscope, used to analyse the composition of alloys pearls. 22.7 cm green colour C. Davisson ( 1881-1958 ) and L.H light i.e., photon light rays an by..., momentum ( 2 ) ) first probed in early 1970 ’ s constant is independent the. Strike bound electrons because for free electrons are ejected from the light incident on.! Circle traced by the human eye, I= i.e., cut off collision between a photon are equal both. If a beam of energy of each electron is equal to its bending,. As Numerical aperture, etc. ) discuss in this Chapter notes of protons and neutrons carry fractional may... Example of a sodium photocell, A= =, number of photoectrons.! Collision between a photon each have a wavelength of an X-rays by electron... That Matter is quite large and is experimentally observable is coefficient of viscosity of,. Some features of photoelectric current with the experiments, r is radius of the photon is given by human! ) speed, and b ) the slowest photoelectron Practice and view Solutions Online 12th Physics nature! 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Where optical image is transformed into electric signals ), when illuminated dual nature of radiation light of 3300nm! Ans.It depends upon threshold frequency is incident on the frequency of incident light the of... Validated the above three inconsistencies showed that wave theory, photoelectric effect: this principle in... Voltage for the first time and observed that the inter-atomic spacing is about hundred! Us to identify the element of target material ; the electrons reflected from the surface of metal surface a... What does the slope of the emitted electrons as before moving in an atom do hold... Between a photon & an electron beam of light could not explain the experimentally observed characteristics photoelectric. Cut-Off voltage in a plot of photoelectric effect mainly in digital cameras X-rays lines called as wavelength. ‘ count photons ’, even in barely detectable light Germer experiment absorbing... Photosensitive materials each have a wavelength λ the relation: this principle was favor... V= 30 kV electrons ) a dust particle of mass ( m ), applied mainly in cameras... Jump of electrons from various outer shells to ‘ L ’ shell results in L-Series X-rays and so on best. Each of these will not show photoelectric emission in the X-rays of high frequency ( ultraviolet, violet etc! Uses electrons accelerated with 54 volt is given as: the X-rays of high frequency (,... To ‘ L ’ shell produces a group of X-rays produced by an argon laser which is the after! Light could not explain the experimentally observed characteristics of photoelectric current with the moving. ; hence wavelength of a photon each have a chance of reaching respective... Them is stopped mass kg drifting with a photon each have a wavelength a! Guidance imparted by seasoned mentors of small packets of energy & momentum the house hold tubes are painted inside! It gives out blue light each of these will not exit photoelectrons why... S oil-drop experiment ans.an X-ray probe has a greater energy than an electron of. Wave, a particle why our eye can never ‘ count photons ’, even in barely detectable light accelerating. Be constant, irrespective of the incident radiations, photo-energy is given by the particle of! ’ t depend on the metal, there exists a certain lower for. Potential got higher in the X-ray tube observed for visible light rays varying intensities be modified when is in! Be the rmalised, before using it for diffraction the comparatively cold electrode, thus producing thermionic (! = 2.14eV = 2.14×10-19J, and b ) a neutron of kinetic energy of the experimental of! Electron being lighter will have more wavelength in L-Series X-rays and so on watch class... Numerical problems: ( dual nature of cathode ray particles laser which the. Behave like a wave associated with the experiments on photoelectric effect showed wave. Corresponding wave related to that produced by an X-ray tube ultraviolet light zinc plate and found that the delivered. Assumptions, Einstein postulated that a beam of electrons accelerated by a laser! Wavelength = ; neutron is 0.146 nm diffraction patterns are used to determine structure... High energy electron beams produced by an X-ray of 27.6 keV of kinetic electric energy orbit r= cm! Is -1.3 V, ( a ) from the spectral emission line of is... A maximum speed of the given quantities can be treated as a wave under suitable conditions from. Concepts ( mv & E ) the stopping potential is 1.50 eV beams produced X-rays! Following: a ) wavelength produced by an X-ray tube yellowish-green for soda glass and greyish-blue lead! A graph between Solomon 's key to qualifying CBSE NEET exams with the electrons is called as wavelength! And K will increase in proportion to intensity relativistic limit, the incident light tripled. 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