STD 12 - Atoms PYQs: JEE Mains Physics – Page 3

Showing 101–131 of 131 questions

101. 101. The first member of the Balmer series of hydrogen atom has a wavelength of \(6561\; \mathring A\). The wavelength of the second member of the Balmer series (in \(nm\)) is 2020 Medium
102. 102. The time period of revolution of electron in its ground state orbit in a hydrogen atom is \(1.6 \times 10^{-16} \;\mathrm{s}\). The frequency of revolution of the electron in its first excited state (in \(s^{-1}\) ) is: 2020 Hard
103. 103. A hydrogen atom, initially in the ground state is excited by absorbing a photon of wavelength \(980\,\mathop A\limits^o \). The radius of the atom in the excited state, in  terms of Bohr radius \(a_0,\) will be \((hc\,=\,12500\,eV-\mathop A\limits^o)\) 2019 Hard
104. 104. A particle of mass \(m\) moves in a circular orbit in a central potential field \(U\left( r \right) = \frac{1}{2}k{r^2}\). If Bohr’s quantization conditions are applied, radii of possible orbits and energy levels vary with quantum number \(n\) as 2019 Hard
105. 105. A particle \(P\) is formed due to a completely inelastic collision of particles \(x\) and \(y\) having de -Broglie wavelengths \({\lambda _x}\) and \({\lambda _y}\) respectively. If \(x\) and \(y\) were moving in opposite directions, then the de -Broglie wavelength of \(P\) is 2019 Medium
106. 106. An excited \(He^+\) ion emits two photons in succession, with wavelengths \(108.5\, nm\) and \(30.4\, nm\), in making a transition to ground state. The quantum number \(n\), corresponding to its initial excited state is \(n=........\) (for photon of wavelength \(\lambda \), energy \(E = \frac{{1240\,eV}}{{\lambda \,(in\,nm)}}\)) 2019 Medium
107. 107. Consider an electron in a hydrogen atom, revolving in its second excited state (having radius \(4.65\, \mathop A\limits^o \)). The de-Broglie wavelength of this electron is....\(\mathop A\limits^o \) 2019 Hard
108. 108. In a hydrogen like atom, when an electron jumps from the \(M -\) shell to the \(L-\) shell the wavelength of emitted radiation is \(\lambda \). If an electron jumps from \(N-\) shell to the \(L-\) shell the wavelength of emitted radiation will be 2019 Medium
109. 109. In \(Li^{++},\) electron in first Bohr orbit is excited to a level by a radiation of wavelength \(\lambda .\) When the ion gets deexcited to the ground state in all possible ways(including intermediate emission) a total of six spectral lines are observed. What is the value of \(\lambda \)?.....\(nm\) (Given: \(h = 6.63\times 10^{34}\,js; e = 3 \times 10^8\,ms^{-1}\) ) 2019 Hard
110. 110. Radiation coming from transition \(n = 2\) to \(n = 1\) of hydrogen atoms fall of \(He^+\) ions in \(n = 1\) and \(n = 2\) states. The possible. Transition of helium ions as they absorb energy from the radiation is 2019 Hard
111. 111. Taking the wavelength of first Balmer line in hydrogen spectrum (\( n = 3\) to \(n = 2\) ) as \(660\,nm ,\) the wavelength of the \(2^{nd}\) Balmer line ( \(n =4\) to \(n = 2\) ) will be....\(nm\) 2019 Hard
112. 112. The electron in a hydrogen atom first jumps from the third excited state to the second excited state and subsequently to the first excited state. The ratio of the respective wavelengths, \(\lambda _1/\lambda _2\), of the photons emitted in this process is 2019 Hard
113. 113. If the series limit frequency of the Lyman series is \(v_L\), then the series limit frequency of the \(P\)-fund series is 2018 Medium
114. 114. Muon \((\mu ^{-1})\) is negatively charged \(\left( {\left| q \right| = \left| e \right|} \right)\) with a mass \(m_{\mu}\, = 200\,m_e\), where \(m_e\) is the mass of the electron and \(e\) is the electronic charge. If \(\mu ^{-1}\) is bound to a proton to form a hydrogen like atom, identify the correct statements \((A)\) Radius of the muonic orbit is \(200\) times smaller than that of the electron \((B)\) the speed of the \(\mu ^{-1}\) in the \(n^{th}\) orbit is \(\frac{1}{{200}}\) times that of the election in the \(n^{th}\) orbit \((C)\) The Ionization energy of muonic atom is \(200\) times more than that of an hydrogen atom \((D)\) The momentum of the muon in the \(n^{th}\) orbit is \(200\) times more than that of the electron 2018 Hard
115. 115. The de-Broglie wavelength \(({\lambda _B})\)  associated with the electron orbiting in the second excited state of hydrogen atom is related to that in the ground  state  \(({\lambda _G})\) by 2018 Medium
116. 116. The energy required to remove the electron from a singly ionized Helium atom is \(2.2\, times\) the energy required to remove an electron from Helium atom . The total energy required to ionize the Helium atom completely is......\(eV\) 2018 Hard
117. 117. According to Bohr's theory, the time averaged magnetic field at the centre (i.e. nucleus) of a hydrogen atom due to the motion of electrons in the \(n^{th}\) orbit is proportional to (\(n =\) principal quantum number) 2017 Medium
118. 118. Some energy levels of a molecule are shown in the figure. The ratio of the wavelengths \(r\) =\(\frac{{{\lambda _1}}}{{{\lambda _2}}}\) is given by
     2017 Medium
119. 119. The acceleration of an electron in the first orbit of the hydrogen atom \((z\, = 1)\) is 2017 Hard
120. 120. A hydrogen atom makes a transition from \(n = 2\) to  \(n = 1\) and emits a photon. This photon strikes a doubly ionized lithium atom \((z = 3)\)  in excited state and completely removes the orbiting electron. The least quantum number for the excited state of the ion for the process is 2016 Hard
121. 121. As an electron makes a transition from an excited state to the ground state of a hydrogen - like atom/ion: 2015 Medium
122. 122. If one were to apply Bohr model to a particle of mass \('m'\) and charge \('q'\) moving in a plane under the influence of a magnetic field \('B',\) the energy of the charged particle in the \(n^{th}\) level will be 2015 Hard
123. 123. The de-Broglie wavelength associated with the electron in the \(n\, = 4\) level is 2015 Medium
124. 124. For \(LED's\)  to emit light in visible region of electromagnetic light, it should have energy band gap in the range of 2014 Medium
125. 125. Hydrogen \((_1H^1),\) Deuterium \((_1H^2)\),singly ionised Helium \((_2He^4)^+\) and doubly ionised lithium \({\left( {{}_3^6Li} \right)^{ + + }}\), all have one electron around the nucleus. Consider an electron transition from \(n = 2\) to \(n = 1\). If the wavelengths of emitted radiation are \(λ_1,λ_2,λ_3\) and \(λ_4\) respectively then approximately which one of the following is correct? 2014 Medium
126. 126. Match List \(- I\) (Experiment performed) with List \(-II\) (Phenomena discovered/associated) and select the correct option from the options given the lists

     List \(- I\)	List \(- II\)
     \((1)\) Davisson and Genner	\((i)\) Wave nature of electrons
     \((2)\) Millikan's oil drop experiment	\((ii)\) Charge of an electron
     \((3)\) Rutherford experiment	\((iii)\) Quantisation of energy levels
     \((4)\) Franck-Hertz experiment	\((iv)\) Existence of nucleus

     2014 Medium
127. 127. The radiation corresponding to \(3 \rightarrow 2\) transition ofhydrogen atom falls on a metal surface to produce photoelectrons. These electrons are made to enter a magnetic field of \(3 \times  10^{-4}\) \(T\) If the radius of the largest circular path followed by these electrons is \(10.0\ mm\), the work function of the metal is close to......\( eV\) 2014 Hard
128. 128. A \(12.5\, eV\) electron beam is used to bombard gaseous hydrogen at room temperature. It will emit 2013 Hard
129. 129. In a hydrogen like atom electron make transition from an energy level with quantum number \(n\) to another with quantum number \((n- 1)\). If \(n > >  1\), the frequency ofradiation emitted is proportional to 2013 Medium
130. 130. In the Bohr 's model of hydrogen-like atom the force between the nucleus and the electron is modified as \(F = \frac{{{e^2}}}{{4\pi {\varepsilon _0}}}\left( {\frac{1}{{{r^2}}} + \frac{\beta }{{{r^3}}}} \right)\), where \(\beta \) is a constant. For this atom, the radius of the \(n^{th}\) orbit in terms of the Bohr radius \(\left( {{a_0} = \,\frac{{{\varepsilon _0}{h^2}}}{{m\pi {e^2}}}} \right)\) is 2013 Hard
131. 131. In the Bohr model an electron moves in a circular orbit around the proton . Considering the orbiting electron to be a circular current loop, the magnetic moment of the hydrogen atom; when the electron is in \(n^{th}\) excited state, is 2013 Hard

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