This quiz works best with JavaScript enabled. Home > Cbse > Class 12 > Science > Physics Part Ii > Class 12 Physics (Part Ii) Chapter 11 Dual Nature Of Radiation And Matter – Quiz 2 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 12 Physics (Part Ii) Chapter 11 Dual Nature Of Radiation And Matter Quiz 2 (41 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. As the intensity of incident light increases, the A) K.E of emitted photo electrons increases. B) K.E of emitted photo electrons decreases. C) Photoelectric current decreases. D) Photoelectric current increases. Show Answer Correct Answer: D) Photoelectric current increases. 2. When photon of energy 'hv' falls on an aluminium plate (work function E$_{0}$ ), photo electrons of maximum kinetic energy 'K' are ejected . If frequency of radiation is doubled, the maximum kinetic energy of the ejected photo electrons will be A) K. B) K+hv. C) K+E$_{0}$. D) 2K. Show Answer Correct Answer: B) K+hv. 3. The dimensional formula for Plancks constant is A) $ML^2T^{-1}$. B) $ML^2T^{-2}$. C) $MLT^{-2}$. D) $ML^{-2}T^1$. Show Answer Correct Answer: A) $ML^2T^{-1}$. 4. Alpha, beta & gamma rays carry same momentum, which has the longest wavelength A) Alpha rays. B) Beta rays. C) Gamma rays. D) All have same wavelength. Show Answer Correct Answer: D) All have same wavelength. 5. Photoelectric effect is A) Emission of electrons by metals when illuminated by light of suitable frequency. B) Emission of electrons by glass when illuminated by light of suitable frequency. C) Emission of electrons by insulators when illuminated by light of suitable frequency. D) Emission of electrons by metals when heated. Show Answer Correct Answer: A) Emission of electrons by metals when illuminated by light of suitable frequency. 6. The energy spent in releasing the photoelectrons from a metal surface is called ..... A) Work function. B) Potential energy. C) Kinetic energy. D) Excitation energy. Show Answer Correct Answer: A) Work function. 7. Thomson's cathode-ray tube experiment demonstrated that A) Cathode rays are streams of negatively charged ions. B) All the mass of an atom is essentially in the nucleus. C) The e/m of electrons is much greater than the e/m of protons. D) The e/m ratio of the cathode-ray particles changes when a different gas is placed in the discharge tube. Show Answer Correct Answer: A) Cathode rays are streams of negatively charged ions. 8. In Which case is electron emission form a metal not known? A) Heating the metal sufficiently. B) Applying a very strong magnetic field to metal. C) Illuminating a metal surface with suitable light. D) None of these. Show Answer Correct Answer: A) Heating the metal sufficiently. 9. The work functions of sodium and copper are respectively 2.0 eV and 4.0 eV. The maximum velocity of an electron emitted by light of wavelength 4000A incident on the surface of a metal is: A) Sodium. B) Copper. C) Both. D) None of these. Show Answer Correct Answer: A) Sodium. 10. The minimum amount of energy required to liberate a photo electron from the metal surface is called as ..... A) Potential energy. B) Work function. C) Cut off energy. D) Threshold frequency. Show Answer Correct Answer: B) Work function. 11. At the stopping potential, photoelectric current is ..... A) Zero. B) Maximum. C) Infinity. D) A constant. Show Answer Correct Answer: A) Zero. 12. Photoelectric effect phenomenon was discovered by: A) Hertz. B) Huygens. C) Newton. D) Maxwell. Show Answer Correct Answer: A) Hertz. 13. In photoelectric effect A) Electric energy is converted into heat. B) Electrical energy its converted into light energy. C) Light energy is converted into electric energy. D) Electric energy is converted into magnetic field. Show Answer Correct Answer: C) Light energy is converted into electric energy. 14. The specific charge of proton is 9.6 x 10$^{7}$ C kg$^{-1}$. What is the specific charge of alpha particle A) 2.4 x 10$^{7 }$C kg$^{-1}$. B) 9.6 x 10$^{5}$ C kg$^{-1}$. C) 4.8 x 10$^{7}$ C kg$^{-1}$. D) 19.2 x 10$^{7}$ C kg$^{-1}$. Show Answer Correct Answer: C) 4.8 x 10$^{7}$ C kg$^{-1}$. 15. If 5% of the energy supplied to a bulb is radiated as visible light, the number of photons of visible light emitted persecond by a 100 W bulb is (assume wavelength of the visible light to be 5.6 x 10$^{-5}$ cm) A) 2 x 10$^{19}$. B) 1.4 x 10$^{19}$. C) 1.4 x 10$^{20}$. D) 2 x 10$^{20}$. Show Answer Correct Answer: B) 1.4 x 10$^{19}$. 16. The phenomenon by which metals emit electrons under the influence of radiation is called ..... A) Interference. B) Photoelectric effect. C) Polarization. D) Ionization. Show Answer Correct Answer: B) Photoelectric effect. 17. The stopping voltage in photoelectric effet depends A) Only on the frequency of incident photon. B) Only on the intensity of the incident light. C) Only on the nature of the surface of metal. D) On the frequency of incident light and the nature of the metal. Show Answer Correct Answer: D) On the frequency of incident light and the nature of the metal. 18. The maximum kinetic energy of the photoelectrons is ..... proportional to the frequency of incident radiation. A) Inversely. B) Directly. C) First directly and then inversely. D) None of these. Show Answer Correct Answer: B) Directly. 19. Two metals A, B have work functions 2 eV and 4 eV respectively. Which metal has lower threshold wavelength for photoelectric effect? A) A. B) B. C) All the above. D) None of the above. Show Answer Correct Answer: B) B. 20. As the intensity increases ..... A) Kinetic energy of Electrons Increases. B) Photo current Increases. C) Frequency Increases. D) Stopping potential decreases. Show Answer Correct Answer: B) Photo current Increases. 21. Observation:Bright blue light liberates photoelectrons from the surface of lithium but red light from the same intensity does not give off any electrons at all.Explanation:The intensity of red light is not sufficient to liberate photoelectrons DOES THE EXPLANATION EXPLAIN THE OBSERVATION? A) YES. B) NO. C) All the above. D) None of the above. Show Answer Correct Answer: B) NO. 22. The rest mass of photon is A) 9.1 x 10$^{-31}$ kg. B) 1.76 x 10$^{-35}$ kg. C) 1 a.m.u. D) Zero. Show Answer Correct Answer: D) Zero. 23. An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is: A) Radio waves. B) Microwaves. C) UV radiations. D) Infrared radiation. Show Answer Correct Answer: C) UV radiations. 24. In photo electric effect, the K.E of electrons emitted from the metal surface depends upon A) Intensity of light. B) Frequency of incident light. C) Velocity of incident light. D) Both intensity and velocity of light. Show Answer Correct Answer: B) Frequency of incident light. 25. The light photon has ..... nature A) Matter. B) Wave. C) Dual. D) Particle. Show Answer Correct Answer: D) Particle. 26. Who proposed the wave-particle duality theory? A) Albert Einstein. B) Louis de Broglie. C) Marie Curie. D) Isaac Newton. Show Answer Correct Answer: B) Louis de Broglie. 27. The work function of a metal surface is 4.14eV. The cut off wavelength of this metal is A) 4125 A$^{o}$. B) 2062.5A$^{o}$. C) 6000 A$^{o}$. D) 3000 A$^{o}$. Show Answer Correct Answer: D) 3000 A$^{o}$. 28. The maximum kinetic energy of photoelectrons emitted from a surface when photons of energy 6 eV fall on it is 4 eV. The stopping potential is A) 4 V. B) 6 V. C) 10 V. D) 2 V. Show Answer Correct Answer: A) 4 V. 29. The alphabet "h" represent ..... constant A) Planck's constant. B) Gravitational. C) Einstein. D) Boltzman. Show Answer Correct Answer: A) Planck's constant. 30. The critical or threshold wavelength for a photosensitive surface is 6000 Angstrom and the wavelength of the incident light is5000 Angstrom. Then the maximum energy of the emitted electrons would be A) 4.1 eV. B) 0.41 eV. C) 0.041 eV. D) 41 eV. Show Answer Correct Answer: B) 0.41 eV. 31. The frequency of the incident radiation below which the photo electric emission is not possible completely is known as ..... frequency A) Threshold. B) Stopping. C) Highest. D) Zero-level. Show Answer Correct Answer: A) Threshold. 32. A 200 W sodium street lamp emits yellow light. The number of photons of yellow light it emits per second is: A) 1.5 x 1020. B) 62 x 1020. C) 3 x 1019. D) 6x 1018. Show Answer Correct Answer: A) 1.5 x 1020. 33. The collector plate in an experiment on photoelectric effect is kept vertically above the emitter plate, light source is put on and a saturation photoelectric current is recorded. An electric field is switched on which has a vertically downward direction A) The threshold frequency will increase. B) The photoelectric current will increases. C) The stopping potential will decreases. D) The kinetic energy of the electron will increases. Show Answer Correct Answer: D) The kinetic energy of the electron will increases. 34. Below the threshold frequency, if the intensity of radiation is increased, the emission of photoelectrons ..... A) Zero. B) Increases. C) Decreases. D) Constant. Show Answer Correct Answer: A) Zero. 35. The slope of frequency of incident ray and stopping potential for a given surface A) E. B) H. C) H/e. D) Eh. Show Answer Correct Answer: C) H/e. 36. For photo electric emission, tungsten requires light of 2300A$^{0}$. If light of 1800 A0wavelength is incident, then emission A) Depends on frequency. B) May or may not take place. C) Take place. D) Does not take place. Show Answer Correct Answer: C) Take place. 37. Who discovered Photoelectric Effect? A) Wilhelm Hallwachs. B) Philipp Lenard. C) Heinrich Hertz. D) Albert Einstein. Show Answer Correct Answer: C) Heinrich Hertz. 38. Photoelectric does not occur when a metal plate is exposed to ultra-violet rays. It will occur if the plate is exposed to A) Radio wave. B) Light wave. C) Infra red rays. D) X-ray. Show Answer Correct Answer: D) X-ray. 39. An electron and proton possessing same amount of kinetic energies. The de-Broglie wavelength is greater for A) Electron. B) Proton. C) Both Electron &Proton. D) None of these. Show Answer Correct Answer: A) Electron. 40. Photoelectric effect is possible A) With only ultraviolet. B) With only visible. C) With only white light. D) With both visible and UV depending on the metal. Show Answer Correct Answer: D) With both visible and UV depending on the metal. 41. To understand photo electric effect, a graph is plotted between two factors which is a straight line. The factors are A) Intensity of radiation and photo electric current. B) Intensity of radiation and stopping potential. C) Threshold frequency and velocity of photons. D) Potential of anode and photo electric current. Show Answer Correct Answer: A) Intensity of radiation and photo electric current. ← PreviousRelated QuizzesScience QuizzesClass 12 QuizzesClass 12 Physics (Part Ii) Chapter 11 Dual Nature Of Radiation And Matter Quiz 1Class 12 Physics (Part Ii) Chapter 10 Wave Optics QuizClass 12 Physics (Part Ii) Chapter 12 Atoms QuizClass 12 Physics (Part Ii) Chapter 13 Nuclei QuizClass 12 Physics (Part Ii) Chapter 14 Semiconductor Electronics Materials QuizClass 12 Physics (Part Ii) Chapter 9 Ray Optics And Optical Instruments Quiz 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books