 |
| Physics 12th Chapter 20 - Atomic Spectra |
Physics 12th Chapter 20 - Atomic Spectra Solved MCQs, Important Short Questions and Long Questions Bank
MCQs
Please select the right answer.
1. The value of Rydberg's constant is
2. According to Bohr, the angular momentum of an electron in the allowed orbit is given by
3. According to Rutherford nuclear model, the major constituents of the nucleus are:
4. After the emission of X-ray, the atom of the target is
5. An electron of the hydrogen atom in the second orbit, is called its:
6. An example of an absorption spectrum is the spectrum of:
7. Atom can reside in metastable state for
8. Atomic spectra are
9. Atomic spectra are the examples of spectra.
10. Balmer series is obtained when all the transitions of electron terminate on:
11. Balmer series lies in
12. Balmer series lies in that region of electromagnetic wave spectrum, which is known as:
13. Balmer series was identified in:
14. Bohr was presented atomic model of hydrogen in:
15. Bohr’s atomic model of hydrogen was proposed by Niel Bohr in
16. Bohr’s postulates explained by:
17. Brackett series is obtained when electronic transitions terminate on the:
18. Brackett series lies in the
19. Braking radiation causes:
20. By CAT scans, we can detect the density difference of the order of:
21. Characteristic x-rays are produced from:
22. Different types of lasers are:
23. During the transition of electron of hydrogen atom from higher orbit to a third orbit, a photon of:
24. Electromagnetic rays which lies above the x-rays region are called:
25. En-Ep=hf is the energy of
26. Energy of hydrogen atom in the ground state is
27. Energy required by an atom to move from ground state to higher energy state is called
28. First spectral series of Hydrogen atoms was discovered by
29. For holography we use a beam of:
30. For Panchen series the value of n starts from
31. For production of X-rays, the target must be of:
32. For the production of x-rays, the target metal should be bombarded by:
33. For the stability of nuclear model, Rutherford proposed:
34. Helium-Neon laser discharge tube contains neon:
35. How many postulates are upon which the Bohr’s theory of hydrogen atom is based
36. Hydrogen atom spectrum does not lie in
37. If an electron jumps from lower to higher orbit it will
38. If electrons jumps from second orbit to first orbit in hydrogen atom it emits photon of:
39. If the ionization energy of hydrogen atom is 13.6 eV, its ionization potential will be:
40. If the radius of first orbit of hydrogen atom is 0.053nm , the radius of second orbit will be
41. If the radius of first orbit of hydrogen atom is 0.53A⁰ , the radius of second orbit will be
42. In 1913, modern tube for production of X-rays was designed by
43. In a electronic transition atom cannot emit:
44. In an electronic transition, an atom cannot emit
45. In Bohr atomic model, the electron does not fall into the nucleus because:
46. In Bohr’s atomic model, the lowest orbit corresponds to:
47. In electronic transition, atom cannot emit:
48. In Helium-Neon laser, discharge tube is filled with Neon gas:
49. In He-Ne laser, the laser action is produced by:
50. In hydrogen atom, which one of the following series lies in the infrared region:
51. In hydrogen spectrum, which one the following series lies in the ultraviolet region:
52. In the general formula for spectral series, if we put P = 3, we get the formula for:
53. In the production of laser beam for each incident photon, we will have two photons going:
54. In the state n=∞ of hydrogen atom, total energy of electron is
55. In which region of electromagnetic spectrum of Hydrogen, the balmer series lies ?
56. K-series of characteristic x-rays spectrum results when all the transitions of inner-shell electrons terminate an:
57. Kß x-ray is emitted when an electron from:
58. Kα- X rays are produced due to transition of electrons from:
59. Laser beam can be used to generate three dimensional images of object in a process called:
60. Laser can be made by creating:
61. Laser is a device which can produce
62. Laser is beam of light which is:
63. Laser is device which can produce:
64. Laser light is
65. Life time of excited state is
66. Life time of metastable states is:
67. Most commonly used type of gas laser is:
68. Most efficient tube for production of x-rays was designed by:
69. mvr is the expression for:
70. Net force on an electron in an orbit around the nucleus will be:
71. Operation of a laser depends upon:
72. Paschen series is obtained when all the transitions of electron terminate on
73. Paschen series lies in the
74. Quality of X-rays depends upon
75. Quality of x-rays depends upon:
76. Radiation with wavelength longer than red light is called
77. Radiation, with wavelength shorter than violet is called:
78. Radius of 3rd Bohr orbit in hydrogen atom is greater than radius of 1 orbit by
79. Real mass of an electron is
80. Reflecting mirrors in laser is used to:
81. Rutherford concluded that central part of an atom is:
82. Rutherford’s nuclear model predicted:
83. Spectrum shows the number of component colour present in certain light in terms of:
84. Speed of the electron in the first Bohr's orbit is:
85. Study of hydrogen visible spectrum in:
86. The Balmer series is obtained when all the transitions of electron terminate on
87. The Bracket series is obtained when all the transitions of electron terminate on
88. The branch of Physics in which laser is studied:
89. The characteristic x-rays appear as:
90. The characteristic x-rays spectrum is due to:
91. The diameter of an atom is of the order of:
92. The dimensions of Planck's constant is same as that of
93. The electric potential energy of an electron in an orbit at a distance rn from the positive charge
94. The energy in electron volt necessary to remove the most loosely bound electron from the neutral atom is known as
95. The energy of electron in ground State of hydrogen atom is -13.6ev, then its energy in forth orbit
96. The energy of the 4th orbit in hydrogen atom is
97. The energy of the electron in the first allowed orbit of hydrogen atom is
98. The excited atoms return to their ground state in
99. The experimental value of Rydberg’s constant is:
100. The first series, which was identified in the spectrum of hydrogen is called:
101. The first spectra line of K-series of characteristics x-rays spectrum results when:
102. The first theory about the structure of an atom was introduced by.
103. The following gas was identified in the sun using spectroscopy:
104. The I Bohr atom in the hydrogen atom has radius:
105. The idea of laser was introduced by:
106. The line spectrum of hydrogen atom contains the spectral lines in the region of
107. The longest wavelength of light which ionizes a hydrogen atom is:
108. The magnitude of Rydberg constant is
109. The maximum frequency in the spectrum from x-rays tube is directly proportional to the:
110. The minimum wavelength of x-rays can further be reduced by:
111. The numerical value of ground state energy fot the hydrogen atom
112. The numerical value of ground state energy of an electron in an orbit is the measure of:
113. The penetrating power of x-rays depends upon their:
114. The penetrating power of x-rays increases with
115. The penetrating power of x-rays is comparable with that of:
116. The photons emitted in inner shell transition are called:
117. The potential required to remove an electron from the atom is called
118. The process by which lesser beam can be used to generate 3- dimensional images of objects is called:
119. The process of formation of spectrum is known as:
120. The radiations emitted from hydrogen filed discharge tube can be analyzed into:
121. The radii of different orbits around the nucleus of an atom is given by:
122. The radius of 1 st Bohr’s orbit for hydrogen is:
123. The radius of 10th orbit in hydrogen atom is:
124. The radius of 3rd Bohr orbit in hydrogen atom is greater than the radius of orbit by a factor of
125. The radius of first Bohr orbit in the hydrogen atom is
126. The radius of the third Bohr orbit in hydrogen atom is greater than the radius of the first orbit by a factor of
127. The residing time of atoms in meta stable state in case of laser action is
128. The rest mass of x-ray photon is
129. The results of spectra obtained by Balmer were expressed in 1896 by:
130. The reverse phenomenon of photoelectric effect is called as:
131. The reverse process of photo-electric effect is called:
132. The scientist who studies the spectrum of hydrogen in visible light, wavelength range was:
133. The SI unit of Rydberg constant is:
134. The simplest spectrum is that of
135. The spectral series that contains transitions terminating on the ground level of hydrogen is called:
136. The transition’s of electrons in the hydrogen atom result in the emission of spectral lines in the:
137. The transitions of inner shell electrons in heavy atoms give rise to the emission of:
138. The uncertainty in its energy will be:
139. The unit of RH (Rydberg's constant) is:
140. The value of Planck’s constant is:
141. The value of radius of 1st Bohr's orbit is
142. The value of Rydberg constant is:
143. The velocity of laser light is:
144. The velocity of x-rays is equal to that of:
145. The x-rays diffraction with crystal was first studied by:
146. Tick the series lies in visible region:
147. Tick the series lies infrared region:
148. Total energy of an electron in an orbit around the nucleus is the sum of
149. Townes and Authers Schowlan is:
150. Wavelength shorter than violet is called
151. What is speed of electron in the first Bohr orbit?
152. What is the color of light emitted from He-Ne Laser?
153. When an electron exist in its lowest state it is called:
154. When an electron jumps from a higher orbit of energy En to a lower orbit of energy Ep, the frequency f of the emitted radiation is given by the relation
155. When electron absorbs energy, it jumps to
156. When x-rays are passed through aluminium sheets, what happens to their thickness:
157. When X-rays are passed through successive aluminum sheets, their hardness
158. Which is not characteristic of LASER?
159. Which is not true for x-rays
160. Which of the following is one of the spectral series of atomic hydrogen:
161. Which of the following series lies in the ultraviolet region?
162. Which of the following series of H-Spectrum lies in ultraviolet region:
163. Which series is visible from the following:
164. Which series lies in the ultraviolet region?
165. X-ray photons can not produce pair production because
166. X-ray photons cannot produce pair production because:
167. X-ray tube used for production of X-rays contains:
168. X-rays are
169. X-rays are
170. X-rays are affected by
171. X-rays are diffracted by crystal but not by a diffraction grating because:
172. X-rays are radiation of
173. X-rays are similar in nature to
174. X-rays are:
175. X-rays are:
176. X-rays can be used to:
177. X-rays can be:
178. X-rays exhibit the phenomenon of
179. X-rays were discovered by
Short Questions
1. Balmer series of hydrogen tom is photographed in the form of a number of lines whose wave length increase from left to right or extreme left line will be the brightest?
2. Bohr's theory of hydrogen atom is based upon several assumptions. Do any of these assumptions contradict classical physics ?
3. Can an electron reside inside the atom ?
4. Can the electron in the ground state of hydrogen photon of energy 13.6 eV or greater than 13.6 eV?
5. Can x- rays be reflected, refracted, diffracted and polarized just like any other waves? Explain.
6. Compute the shorter wavelength radiation in the Balmer series?
7. Define excitation energy?
8. Define ionization energy?
9. Describe the atomic processes in the target of an X – rays tube whereby X - rays line spectra are produced?
10. Explain the terms:- (A). Excitation Potential (B). Ionization potential
11. Explain the working of a Cat – scanner?
12. Explain what is difference between laser light and light from incandescent light?
13. Explain why a glowing gas gives only certain wavelength of light and why that is capable of absorbing the same wavelength? Give a reason why it is transparent to other wavelengths?
14. Explain why laser action could not accur without population inversion between atomic levels?
15. Find the speed of an electron in the first Bohr orbit ?
16. How can the hydrogen spectrum contain so many lines although hydrogen contains one electron only?
17. How does a meta stable state differ from a normal excited state of an atom?
18. How many electronic orbits are there in a hydrogen atom ?
19. Hydrogen gas at atom – temperature absorbs tight of wavelengths equal to the lines in the Lyman series but not those of the Blamer series? Explain.
20. In what region does Balmer series lie?
21. In what region does Braket series lie?
22. In what region does Lyman series lie ?
23. In what region does Paschen series lie?
24. In what region does Pfund series lie ?
25. Is energy conserved when an atom emits a photon of light?
26. List the colour of line spectra of an excited hydrogen atom?
27. Name the types of lasers ?
28. Name the types of spectra ?
29. What is the value of Plank's constant ?
30. When an atom is said to be ionized ?
31. State the three postulates of Bohr’s theory of atomic structure?
32. The electromagnetic wave energy emitted in space by a point source obeys inverse square law ?
33. The electron in a hydrogen atom requires an energy of 10.2 eV for excitation to a higher energy level . A photon and an electron each of energy 10.5 eV are incident upon the atom which of these can excite the atom? Give explanation in support of your answer?
34. The hydrogen atom contains only a single electron and yet the hydrogen spectrum contains may lines?
35. The orbital electron of a hydrogen atom moves with a speed of 5.456 x 10⁵ ms¹ find the value of quantum number 'n' associated with this electron ?
36. V. If these electrons were slowed down in a target. What will be the minimum wavelength of x-rays produced ?
37. What are characteristic X-rays ?
38. What are different kinds of lasers?
39. What are infra-red radiations ?
40. What are main characteristics of a line spectrum? Explain how line spectra can be used for the identification of elements?
41. What are the advantages of laser over ordinary light?
42. What are X –rays?
43. What do you mean by a stationary orbit as postulated by Bohr ?
44. What do you mean by helium-neon laser ?
45. What do you understand by excitation energy and ionization energy?
46. What does the name Laser stand for. Define it?
47. What is a CAT scanner?
48. What is atomic spectrum ?
49. What is band spectrum ?
50. What is continuous spectrum ?
51. What is difference between the terms normal population and population inversion ?
52. What is excited state ?
53. What is ground state ?
54. What is inner shell transition of electron?
55. What is laser principle?
56. What is Laser?
57. What is line spectrum ?
58. What is meant by a line spectrum? Explain, how line spectrum can be used for the identification of elements?
59. What is metastable state?
60. What is spectroscopy?
61. What is spectrum ?
62. What is spontaneous Emission?
63. What is stimulated emission ?
64. What is the energy of electron of hydrogen atom in the first orbit (ground state)?
65. What is the net force on an electron in an orbit revolving around the nucleus ?
66. What is the ordinary life time of an electron in the excited state ?
67. What is the total energy of an electron of hydrogen atom?
68. What is the value of ionization energy of hydrogen atom?
69. What is the value of radius of first Bohr orbit?
70. What is the value of Rydberg's constant ?
71. What is the wave length range of x-rays ?
72. What is the word 'laser' stands for ?
73. What is uncertainty with the atom regarding to position of electrons ?
74. When an atom is said to be excited ?
75. When did Neil Bohr propose a model of hydrogen atom ?
76. When did Rontgen discover x-rays ?
77. Whether black body radiation spectrum is a continuous spectra ?
78. Whether molecular spectra are the example of band spectra ?
79. Which laser is mist commonly used ?
80. Why do you mean when say that the atom is excited?
81. Why does laser usually emit only one particular color of light rather than several colors?
82. Why does solids give rise to a continuous spectrum while hot gases gives rise to line spectrum?
83. Why does the frequencies of characteristic X – rays depend upon the type of material used for the target?
84. Write any four properties of x-rays ?
85. Write any four uses of x-rays ?
86. Write down some applications of laser?
87. Write some important uses of laser?
Long Questions
1. Explain atomic spectrum / spectra?
2. Write Bohr’s second postulate and find out formula for Bohr quantized radii.
3. Define spectroscopy. Derive expression for radii of quantized orbit.
4. What is hydrogen emission spectrum?
5. What are X-rays? How are they produced?
6. What is CAT-Scanner?
7. What is the biological effects of X-rays?
8. Explain characteristics X-rays and continuous X-ray spectra. Also write two uses of X-rays.
9. Explain the uncertainty within the atom.
10. What does the word laser stand for? Write any four uses of laser.
11. A hydrogen atom is in its ground state (n = 1). Using Bohr’s theory, calculate (a) the radius of the orbit, (b) the linear momentum of the electron, (c) the angular momentum of the electron, (d) the kinetic energy, (e) the potential energy, and (f) the total energy.
12. What are the energies in eV of quanta of wavelength 400, 500 and 700 nm?
13. An electron jumps from a level Ei = -3.5 x 10⁻¹⁹J to Ef = -2 x 10⁻¹⁸J. What is the wavelength of the emitted light?
14. Find the wavelength of the spectral line corresponding to the transition in hydrogen from n = 6 state to n = 3 state.
15. Compute the shortest wavelength radiation in the Balmer series? What value of n must be used?
16. Calculate the longest wavelength of radiation for the Paschen series.
17. Electron in an x-ray tube are accelerated through a potential difference of 3000V. If these electrons were slowed down in a target, what will be the minimum wavelength of x-ray produce?
18. The wavelength of K-x-ray from copper is 377 x 10⁻¹⁰ m. What is the energy difference between the two levels from which this transition results?
19. A tungsten target is struck by electrons that have been accelerated from rest through 40KV potential difference. Find the shortest wavelength of the bremsstrahlung radiation emitted?
20. The orbital electron of a hydrogen atom moves with a speed of 5.456 x 10⁵ ms⁻¹, (a) find the value of the quantum number ‘n’ associated with this electron, (b) calculate the radius of this orbit, and (c) the energy of the electron in this orbit?