Tiêu đề 26. Dual Nature Of Radiation And Matter.pdf ✅

1. A potential difference of 20 k V is applied across an X- ray tube. The minimum wave length of X-rays generated (in Å) is - (1) 0.62 (2) 1.24 (3) 0.31 (4) 6.2 2. If 5 % of the energy supplied to a bulb is irradiated as visible light, how many quanta are emitted per sec by a 100 watt lamp? Assume wavelength of visible light as 5.6 × 10–5 cm. (1) 1.4 × 1019 (2) 2.0 × 10–4 (3) 1.4 × 10 –19 (4) 2.0 × 104 3. The ratio of de Broglie wavelength of molecules of hydrogen and helium in two gas jars kept separately at temperatures of 27° C and 127°C respectively is :- 4. The work function of caesium is 2.14 eV. Find the wavelength of the incident light if the photo current is brought to zero by a stopping potential of 0.60 volt : (1) 454 nm (2) 640 nm (3) 540 nm (4) None of these 5. If two particles have equal de Broglie wavelength then they must have equal magnitude of :- (1) Speed (2) Kinetic energy (3) Momentum (4) Charge 6. In the experiment of experiment of photo electric effect, wavelength of light is  and minimum deBroglie wavelength of photo electrons is ( ) '  .Threshold wavelength of metal 0 . Correct relation is (m = mass of electron) :- (1) ' 2 0 1 1 2 ( ) h    mC = = (2) ' 0 1 1 1    m( ) = = (3) 2 ' 2 0 1 1 2 ( ) h    mC = = (4) 2 ' 2 0 1 1 2 ( ) h    mC = = 7. If kinetic energy of an electron is increased by 4%then percentage change in de-Broglie wavelength:- (1) decreases by 2% (2) decreases by 1% (3) increases by 5% (4) None of these 8. A photon of energy E ejects a photoelectron from a metal surface whose work function is W0. If this electron enters into a uniform magnetic field of induction B in a direction perpendicular to the field and describes a circular path of radius r, then the radius r is given by: (in the usual notation)- 9. A photon of energy 8 eV is incident on a metal surface of threshold frequency 1.6 × 1015 Hz. The maximum kinetic energy of photo electrons emitted is -(Take h = 6.6 × 10–34 J-s; 1 eV = 1.6 × 10–19 J) (1) 1.4 eV (2) 0.8 eV (3) 4.2 eV (4) 2.8 eV 10. An  -particle and a deutron are moving with velocities v and 2v respectively. What will be the ratio of their de Broglie wavelengths – (1) 1 : 1 (2) 2 :1 (3) 1: 2 (4) 2 : 1 Assertion & Reason a) Both (A) and (R) are true and (R) is the correct explanation of (A) b) Both (A) and (R) are true and (R) is not the correct explanation of (A) c) (A) is true statement but (R) is false d) Both (A) and (R) are false 11. Assertion :-Photoelectric current is function ofdistance between light source and photo cell. Reason :-There is one-one interaction between photon and electron. Dual Nature of Radiation and Matter
(1) a (2) b (3) c (4) d 12. 10–3 watt and 5000 Å light is directed on a photoelectric cell. If the current in the cell is0.16 A, the percentage of incident photons which produce photoelectrons, is (1) 0.4% (2) 0.04% (3) 20% (4) 10% 13. In a photoelectric experiment, the potential difference V that must be maintained between the illuminated surface and the collector so as just to prevent any electron from reaching the collector is determined for different frequencies f of the incident illumination. The graph obtained is shown. The maximum kinetic energy of the electrons emitted at frequency f1 is :- 14. The graph is showing the photocurrent with the applied voltage of a photoelectric effect experiment. Then :- (1) A & B will have same intensity and B & C have same frequency (2) B & C have same intensity and A & B have same frequency (3) A & B will have same frequency and B & C have same intensity (4) A & C will have same intensity and B & C have same frequency 15. Electrons with de-Broglie wavelength  fall on the target in an X-ray tube. The cut-off wavelength of the emitted X-rays is :- 16. The metallic surface is illuminated with monochromatic light of wavelength  and stopping potential for photoelectric current is 5V0.When the same metallic surface is illuminated with a light of wavelength  , the stopping potentials is V0. What is the threshold wavelength for the surface ? (1) 8 3  (2) 8 (3) 5 (4) 4 17. The cathode of a photoelectric cell is changed such that the work function changes from W1 toW2 (W2 > W1). If the current before and after change are I1 and I2, all other conditions remaining unchanged, then (assuming hv>W2) (1) I1 = I2 (2) I1< I2 (3) I1> I2 (4) I1< I2< 2I 18. Assertion :-When electron travels with speed of light, it becomes a wave. Reason :- Matter waves travel with speed of light. (1) a (2) b (3) c (4) d 19. A particle is dropped from a height H. The de-Broglie wavelength of the particle as a function of height is proportional to :- (1) H (2) H1/2 (3) H0 (4) H-1/2 20. A l00 watt light source is emitting radiations of wavelength 5000Å. The rat e of emission of photons is of the order of : (1) 1040 (2) 1020 (3) 1010 (4) 105 21. If the frequency of light in a photo electric experiment is doubled, the stopping potential will:- (1) be doubled (2) be halved (3) become more than double (4) become less than double 22. A photon and an electron have equal energy E /   photon electron is proportional to :- 1) E 2) 1 E
3) 1 E 4) Does not depend upon E 23. An electron is moving with an initial velocity 0 ˆ v v j = and is in a magnetic field 0 B B k ˆ = . Then its de Broglie wavelength:- (1) Remains constant (2) Increases with time (3) Decreases with time (4) Increases and decreases periodically. 24. The surface of a metal is illuminated with light of400 nm. The maximum kinetic energy of the ejected photoelectrons was found to be 1.68 eV. The work function of the metal is : (hc = 1240 eV nm) (1) 3.09 eV (2) 1.42 eV (3) 1.51 eV (4) 1.68 eV 25. The wavelength of most energetic X-rays emitted when a metal target is bombarded by 40 keV electrons, is approximately:- (1) 300 Å (2) 10 Å (3) 4 Å (4) 0.31 Å 26. If p and  be the de-Broglie's wave lengths associated with protons and  -particles of equal kinetic energies, then (1) 4 p   = (2) 2 p   = (3)   p =  (4) 2   p =  27. When light is incident on surface, photo electrons are emitted. For photo electrons : (1) The value of kinetic energy is same for all (2) Maximum kinetic energy do not depend on the wave length of incident light (3) The value of kinetic energy is equal to or less than a maximum kinetic energy (4) None of the above. 28. If E and P are the energy and the momentum of a photon respectively then on reducing the wavelength of photon - (1) P and E both will decrease (2) P and E both will increase (3) P will increase and E will decrease (4) P will decrease and E will increase 29. The work function of a surface of a photo sensitive material is 6.2 eV. The wavelength of the incident radiation for which the stopping potential is 5Vlies in the:- (1) Infrared region (2) X-ray region (3) Ultraviolet region (4) Visible region 30. Threshold wavelength of a metal surface is 5×10–10 m. When it is illuminated by light of wavelength 2×10–10 m , stopping potential is V0what will be stopping potential if wavelength of light is doubled :- (1) 0 2 V (2) 0 2V (3)  (0.5V0 ) (4)  (0.5V0 ) 31. A photon of energy h is absorbed by a free electron of a metal having work function    h :- (1) The electron is sure to come out (2) The electron is sure to come out with a kinetic energy h − (3) Either the electron doesn’t come out or it come out with a kinetic energy h − (4) It may come out with kinetic energy less than h −
32. Light of wavelength  strikes a photo sensitive surface and electrons are ejected with kinetic energy E. If the kinetic energy is increased two time, (i.e., 2E), the wavelength must be changed to '  , where:- (1) ' 2      (2) '    (3) ' 2   = (4) ' 2    33. An electron with speed v and a photon with speed c have the same de-Broglie wavelength. If the kinetic energy and momentum of electrons is Ee and pe and that of photon is Ep and pp respectively, then the correct statement is:- (1) e 2 p E c E v = (2) e 2 p P c P v = (3) p 2 e E c E v = (4) p 2 e P c P v = 34. The work function of metal is 1 eV. Light of wavelength 3000Å is incident on this metal surface. The maximum velocity of emitted photo-electrons will be :- (1) 10 m/s (2) 1 × 103 m/s (3) 1 × 104 m/s (4) 1 × 106 m/s 35. Figure represents the graph of photo current I versus applied voltage (V). The maximum kinetic energy of the emitted photoelectrons is:- (1) 2eV (2) 4eV (3) 0 eV (4) 4 J 36. Light of wavelength 5000 Å is falling on a sensitive surface. If the surface has received 10–7 J of energy, then the number of photons falling on the surface will be - (1) 5 × 1011 (2) 2.5 × 1011 (3) 3 × 1011 (4) none of these 37. An  −particle and a deutron are moving with velocities v and 2v respectively. What will be the ratio of their de Broglie wavelengths - (1) 1 : 1 (2) 2 :1 (3) 1 : 2 (4) 2 : 1 38. Calculate the energy of photon having  = 1000Åin Joule. (1) 4.96 × 10–19 J (2) 9.92 × 10–19 J (3) 19.84 × 10–19 J (4) 12.4 J 39. A proton and electron are accelerated through same potential, then e p   will be :- (1) 1 (2) / m m e p (3) / m m p e (4) / m m p e 40. The work function of a metal is 2.3 eV and the maximum kinetic energy of photo electrons is0.3 eV when photon is incident on it. Find the wavelength of incident photon. (1) 4800Å (2) 2400Å (3) 1200Å (4) 600Å 41. Energy of an electron and photon are equal. If wavelength of electron is 1Å then wavelength of the photon is approx:- (1) 82.67 Å (2) 1 Å (3) 124 Å (4) 1.67 Å 42. The photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly :-