Title DUAL NATURE OF RADIATION AND MATTER.docx.pdf ✅

11.DUAL NATURE OF RADIATION AND MATTER Single Correct Answer Type 1. Energy conversion in a photoelectric cell takes place form a) Chemical to electrical b) Magnetic to electrical c) Optical to electrical d) Mechanical to electrical 2. A uniform electric field and a uniform magnetic field are acting along the same direction in a certain region. If an electron is projected along the direction of the fields with a certain velocity, then a) Its velocity will decrease b) Its velocity will increase c) It will turn towards right of direction of motion d) It will turns towards left of direction of motion 3. Which phenomenon best supports the theory that matter has a wave nature a) Electron momentum b) Electron diffraction c) Photon momentum d) Photon diffraction 4. Consider the following statements concerning electrons : I. Electrons are universal constituents of mater. II. J J Thomson received the very first Nobel prize in Physics for discovering the electron. III. The mass of the electron is about 1/2000 of a neutron. IV. According to Bohr the linear momentum of the electron is quantised in the hydrogen atom. Which of the above statements are not correct? a) I b) II c) III d) IV 5. The working principle of the mass spectrograph is that for a given combination of accelerating potential and magnetic field, the ion beam (with charge q and mass M) to be collected at different positions of ion collectors will depend upon the value of a) q/M b) (q/M) 2 c) q/M d) qM 6. An electron of K spectral line of an atom is then the wavelength of line will be α 59 keV, Kα a) 0. 20 Å b) 0. 42 Å c) 0. 31 Å d) 0. 62 Å 7. The de-Broglie wavelength λ associated with an electron having kinetic energy E is given by the expression a) h 2mE b) 2h mE c) 2mhE d) 2 2mE h 8. Electric field and magnetic field in Thomson mass spectrograph are applied a) Simultaneously, perpendicular b) Perpendicular but not simultaneously c) Parallel but not simultaneously d) Parallel simultaneously 9. If the wavelength of light is 4000 Å, then the number of waves in 1 mm length will be a) 25 b) 0.25 c) 0. 25×10 4 d) 25×10 4 Page| 1
10. Two identical metal plates shown photoelectric effect by a light of wavelength λÅ falls on plate A and λ on B plate B λ The maximum kinetic energy is A = 2λ B ( ). a) 2 K A = K B b) K A < K B /2 c) K A = 2K B d) K A = K B /2 11. The linear momentum of photon is p. The wavelength of photon is λ , then (h is Planck constant) a) λ = hp b) λ = h p c) λ = p h d) λ = p 2 h 12. A 100 W light bulb is placed at the centre of a spherical chamber of radius 0.10m. Assume that 66% of the energy supplied to the bulb is converted into light and that the surface of chamber is perfectly absorbing. The pressure exerted by the light on the surface of the chamber is a) 0. 87×10 Pa −6 b) 1. 77×10 Pa −6 c) 3. 50×10 Pa −6 d) None of these 13. The speed of an electron having a wavelength of 10 is −10 m a) 7. 25×10 6 m/s b) 6. 26 × 10 6 m/s c) 5. 25×10 6 m/s d) 4. 24 × 10 6 m/s 14. A proton, a deuteron and an α-particle having the same momentum, enters a region of uniform electric field between the parallel plates of a capacitor. The electric field is perpendicular to the initial path of the particles. Then the ratio of deflections suffered by them is a) 1 :2 :8 b) 1 :2 :4 c) 1 :1 :2 d) None of these 15. For harder X-rays a) The wavelength is higher b) The intensity is higher c) The frequency is higher d) The frequency is higher 16. Momentum of a photon is p. The corresponding wavelength is a) h/ p b) p/h c) ph d) h/p 17. Penetrating power of X-rays depends on a) Current flowing in the filament b) Applied potential difference c) Nature of the target d) All the above 18. If V be the accelerating voltage, then the maximum frequency of continuous X-rays is given by a) eh V b) hV e c) eV h d) h eV 19. Solid targets of different elements are bombarded by highly energetic electron beams. The frequency (f) of the characteristic X-rays emitted from different targets varies with atomic number Z as a) f ∝ Z b) f ∝ Z 2 c) f ∝ Z d) f ∝ Z 3/2 20. If the momentum of an electron is changed by ∆p, then the de-Broglie wavelength associated with it changes by 0.50%. The initial momentum of the electron will be Page| 2
a) ∆p 200 b) ∆p 199 c) 199 ∆p d) 400 ∆p 21. If the potential difference between the anode and cathode of the X-ray tube is increase a) The peaks at R and S would move to shorter wavelength b) The peaks at R and S would remain at the same wavelength c) The cut off wavelength at P would increase d) (b) and (c) both are correct 22. If the wavelength of incident light changes from 400 nm to 300 nm, the stopping potential for photoelectrons emitted from a surface becomes approximately a) 1.0 V greater b) 1.0 V smaller c) 0.5 V greater d) 0.5 V smaller 23. In a photoelectric experiment for 4000 Å incident radiation, the potential difference to stop the ejection is 2V.If the incident light is changed to 3000 Å, then the potential required to stop the ejection of electrons will be a) 2 V b) Less than 2V c) Zero d) Greater than 2 V 24. If a photon has velocity c and frequency v, then which of following represents its wavelength a) hc E b) hv c c) hv c 2 d) hv 25. What is de-Broglie wavelength of electron having energy 10 ke V? a) 0. 12Å b) 1. 2Å c) 12. 2Å d) None of these 26. An oil drop with charge q is held stationary between two plates with an external potential difference of 400 V. If the size of the drop is doubled without any change of charge, the potential difference required to keep the drop stationary will be a) 400 V b) 1600 V c) 3200 V d) 4000 V 27. Planck’s constant has the dimensions of a) Energy b) Mass c) Frequency d) Angular momentum 28. The work function of a metal is a) The energy for the electron to enter into the metal b) The energy for producing X-ray c) The energy is required for an electron to come out from metal surface d) None of these 29. An oxide coated filament is useful in vacuum tubes because essentially Page| 3
a) It has high melting point b) It can withstand high temperatures c) It has good mechanical strength d) It can emit electrons at relatively lower temperatures 30. The photoelectric effect can be understood on the basis of a) The principle of superposition b) The electromagnetic theory of light c) The special theory of relativity d) Line spectrum of the atom 31. In a photocell bichromatic light of wavelength 2475 Å and 6000 Å are incident on cathode whose work function is 4. 8 eV.If a uniform magnetic field of 3×10 exists parallel to the plate, the radius of the −5 tesla path described by the photoelectron will be (mass of electron = 9×10 ) −31 kg a) 1 cm b) 5 cm c) 10 cm d) 25 cm 32. The de-Broglie wavelength is proportional to a) λ ∝ 1 v b) λ ∝ 1 m c) λ ∝ 1 p d) λ ∝ p 33. Intensity of X-rays depends upon the number of a) Electrons b) Protons c) Neutrons d) Positrons 34. If the mass of neutral = 1. 7×10 kg, then the de-Broglie wavelength of neutral of energy 3eV is −27 (h = 6. 6×10 −34 J − s) a) 1. 6×10 m −16 b) 1. 6×10 m −11 c) 1. 4×10 m −10 d) 1. 4×10 m −11 35. The work functions of metals A and B are in the ratio 1:2. If light of frequencies f and 2f are incident on the surfaces of A andB respectively, the ratio of the maximum kinetic energies of photoelectrons emitted is (f is greater than threshold frequency of A, 2f is greater than threshold of B) a) 1 :1 b) 1 :2 c) 1 :3 d) 1 :4 36. The minimumwavelength of X-rays produced in a coolidge tube operated at potential difference of 40 kV is a) 0. 31 Å b) 3. 1 Å c) 31 Å d) 311 Å 37. If threshold wavelength for a certain metal is 2000Å, then the work function of metal is a) 6.2 MeV b) 6.2 keV c) 6.2 J d) 6.2 eV 38. The energy of a photon of light with wavelength 5000 Å is approximately 2. 5 eV. This way the energy of an X-ray photon with wavelength 1Å would be a) 2. 5/5000 eV b) 2. 5/(5000) 2 eV c) 2. 5×5000 eV d) 2. 5×(5000) 2 eV 39. An electron is accelerated through a potential difference of V volt. The speed of electrons will be a) eV m b) 2eV m c) eV 2m d) m 2eV Page| 4