Question 1 : The Bohr orbit radius for the hydrogen atom $(n = 1)$ is approximately $0.530 \mathring{A}$ The radius for the first excited state $(n = 2)$ will be:

Question 2 : For which of the following, the radius will be same as for hydrogen atom having $n=1$?

Question 4 : The ratio of velocity of the electron in the third and fifth orbit of $Li^{2+}$ would be:

Question 5 : <div>State True or False.<br/></div>A negative energy state is more stable relative to a zero energy state.<br/>

Question 6 : For the hydrogen atom, the energy of the electron in the $n$th orbit is given by $E=\dfrac{-13.6}{n^{2}}\ eV$, where $n$ is an integer. The smallest amount of energy that a hydrogen atom can absorb in its ground state is:

Question 7 : In the hydrogen atom an electron is moving in nth orbit. The circumference s of the orbit and the de Broglie wavelength, of the moving electron are related by the equation

Question 8 : The approximate value of quantum number $'n\ '$ for the circular orbit of hydrogen of $0.0001\space mm$ in diameter is

Question 9 : The ionization energy of hydrogen atom is $13.6eV.$ The energy required to excite the electron in a hydrogen atom from the ground state to the first excited state is:<br>

Question 10 : &#160;Bohr's radius for the fifth orbit of the hydrogen atom in $A^0$ is :

Question 11 : The energy of second orbit of hydrogen is equal to the energy of:

Question 12 : As an electron is brought from an infinite&#160;distance close of nucleus of the atom, the energy&#160;of electron:

Question 13 : $E_n = - \dfrac{313.6}{n^2}$, if the value of $E_n = - 34.84$ to which value 'n' corresponds:

Question 14 : The ionisation energy for excited hydrogen atom in eV will be :

Question 15 : Calculate the radius of Bohr's first orbit for hydrogen atom and the energy of electron in this orbit:

Question 16 : A small particle of mass $m$ moves in such a way that $P.E=-\displaystyle \frac{1}{2}mkr^{2}$, where $k$ is a constant and $r$ is the distance of the particle from origin. Assuming Bohr's model of quantization of angular momentum and circular orbit, $r$ is directly proportional to:

Question 17 : From which of the following the hydration energy of $Mg^{2+}$ is larger

Question 18 : What is the maximum number of electrons present in the main energy level in which the 'g' subshell appears for the first time?

Question 19 : According to the Bohr model of the atom, which electron transition will emit the lowest energy photon?

Question 20 : According to de-Broglie wavelength for electron in an orbit of hydrogen atom is $10^{-9}\ m$. The principle quantum number for this electron is

Question 21 : A hydrogen atom in the ground state is excited by monochromatic radiation of wavelength $\lambda\ A$ The resulting spectrum consists of maximum $15$ different lines. What is the wavelength$\left( \lambda \right)$ of radiation?$ \left( Given:{ R }_{ H }=109737{ cm }^{ -1 } \right)$

Question 22 : The energy required for removal of electron from $3s, 3p, 3d$ subshells of hydrogen atom will lie in following sequence:<br>${ E }_{ 1 }=\left( 3s\longrightarrow \infty \right) { E }_{ 2 }=\left( 3p\longrightarrow \infty \right) { E }_{ 3 }\left( 3d\longrightarrow \infty \right) $

Question 23 : For the energy levels in an atom which one of the following statements is(are) correct?

Question 24 : The velocity of electron in second shell of hydrogen atom is :<br/>

Question 25 : The wavelength of the radiation emitted, when in a hydrogen atom electron falls from infinity to stationary state, would be: [Rydberg constant = $1.097\times { 10 }^{ 7 }\ { m }^{ -1 }$]

Question 26 : The radius of the second Bohr orbit for hydrogen atom is:<div><br/>[Given: Planck's const. $h = 6.6262\times 10^{-34}Js$; mass of electron $= 9.1091\times 10^{-31}kg$; charge of electron, $e=1.60210\times 10^{-19}C$; permittivity of vacuum, $\varepsilon&#160;_0=8.854185\times 10^{-12}kg^{-1}m^{-3}A^2$]<br/></div>

Question 27 : The total energy of an electron in the ground state of the hydrogen atom is -13.6 eV. The kinetic energy of an electron in the first excited state is:<br/>

Question 28 : Among 4p, 4s, and 3d orbitals, 3d orbital has the least energy.

Question 29 : If m and e are the mass and charge of the revolving electron in the orbit of radius r for hydrogen atom, the total energy of the revolving electron will be:

Question 30 : What is likely to be principal quantum number for a circular orbit of diameter 20 nm of the hydrogen atom, if we assume Bohr orbit be the same as that represented by the principal quantum number?

Question 31 : In one revolution round the hydrogen nucleus, an electron makes five crests .The electron belongs to<br>

Question 32 : The ionisation energy for the H atom is 13.6 eV then the requried energy in eV to excite it from the ground state to next higher state will be (in eV)&#160;:

Question 33 : The ratio of $\left({E}_{2}-{E}_{1}\right)$ to $\left({E}_{4}-{E}_{3}\right)$ for the hydrogen atom is approximately equal to:

Question 34 : An electron in a hydrogen atom in its ground state absorbs energy equal to the ionization energy of $Li<br/>^{{\text{ + 2}}} <br/>$. The wavelength of the emitted electron is:<br/>

Question 35 : The ionization enthalpy of hydrogen atom is $1.312\times 10^{6}\ \mathrm{J}$ mol$^{-1}$. The energy required to excite the electron in the atom from $\mathrm{n}=1$ to $\mathrm{n}=2$ &#160;is&#160;:&#160;<br/>

Question 36 : The longest wave length radiation emitted in the emission spectrum when the pion de-excites from n = 3 to ground state lies in which of the following region?

Question 37 : The energy of the second Bohr orbit in the hydrogen atom is $-3.41 \,eV.$ The energy of the second Bohr orbit of $He^{+}$ ion would be:

Question 38 : The total energy of a hydrogen atom in its ground state is $-13.6\ eV$. If the potential energy in the first excited state is taken as zero then the total energy in the ground state will be:

Question 39 : If the PE of a Bohr's hydrogen atom in the ground state is zero, then its total energy in the first excited state will be :

Question 40 : <div>For $H$-like atoms :</div><div>&#160; &#160; &#160;&#160;</div><div>&#160; &#160; &#160; &#160; &#160; &#160; $\displaystyle E_n=-\frac{Z^2Rh}{n^2};u_n=\frac{u_1Z}{n}$ and $r_n=\frac{r_1\times n^2}{Z};$ where $Rh$ is Rydberg.<br/></div><br/>What is the potential energy of electron in $2^{nd}$ orbit of $H$-atom?<br/>

Question 41 : The ionization energy of hydrogen atom is $13.6$ eV.&#160;The longest wavelength of hydrogen spectrum in&#160;the ultraviolet region is expected to be:

Question 42 : Calculate the ratio of energies of $2^{nd}$ orbits of hydrogen, $He^+, Li^{+2}$.<br/>

Question 43 : A particle of mass $m$ moves around in a circular&#160;orbit in a centro symmetric potential field u(r)$=\dfrac{kr^{2}}{2}$. Using Bohr&#8217;s quantization rule, the permissible&#160;energy levels are&#160;<br/>

Question 44 : The ratio of ground state energy of $Li^{2+},&#160;He^+$ and H is :

Question 45 : Number of waves made by the pion when orbiting in third excitation state are