Question 1 :
If r is radius of first orbit, the radius of nth orbit of the H atom will be :

Question 3 :
<div>State True or False.<br/></div>The velocity of the electron is maximum in the Bohr's last orbit.

Question 4 :
The total energy of the electron revolving around the nucleus is:

Question 5 :
Energy of the electron in hydrogen in its first orbit is:

Question 6 :
Which of the following in relation to the energy of sublevels in H atom is incorrect?

Question 7 :
There are seven orbitals in a subshell then the value of $l$ for it will be

Question 8 :
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 9 :
<div>Assertion (A): Hydrogen has one electron in its orbit but it produces several spectral lines.</div><div>Reason (R): There are many excited energy levels available.<br></div>

Question 11 :
The ratio of the momentum of a proton and a&#160;$\alpha $ - particle which is accelerated from rest by a potential difference of 200 V.&#160;$m_{p}$ and $m_{\alpha }$ are masses of the proton and ${\alpha }$- particles:&#160;

Question 12 :
Which one of the following does not contains electrons in $4s$ subshells?<br/>Given that : Atomic numbers: $Ti=22,V=23,Cr=24,Mn=25$

Question 13 :
According to the Bohr model of the atom, which electron transition will emit the lowest energy photon?

Question 14 :
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 15 :
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 16 :
Consider a hydrogen like atom whose energy in $\displaystyle { n }^{ th }$&#160;excited state is given by $\displaystyle { E }_{ n }=-\frac { 13.6 }{ { n }^{ 2 } } { Z }^{ 2 }$. When this excited atom makes a transition from an excited state to ground state. The most energetic photons have energy $\displaystyle&#160;{ E }_{ max }=52.224eV$&#160;and the least energetic photons have energy&#160;$\displaystyle&#160;{ E }_{ min }=1.224eV$. Find the atomic number of atom.<br/>

Question 17 :
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 18 :
Calculate the ratio of energies of $2^{nd}$ orbits of hydrogen, $He^+, Li^{+2}$.<br/>

Question 19 :
Electrons accelerated by potential V are diffracted from a crystal. If $\mathrm{d}= 1\mathrm{A}$ and $\mathrm{i}=30^{0},\ \mathrm{V}$ should be about:&#160;<div>[$\mathrm{h}=6.6\times 10^{-34}$ Js, $\mathrm{m}_{\mathrm{e}}=9.1\times 10^{-31}$ kg, $\mathrm{e}=1.6\times 10^{-19}\mathrm{C}$]<br/></div>

Question 20 :
If the wavelength of the photon emitted from an electron jump n $=$ 4 to n $=$ 2 in a H-like species is 1216 $\overset{o}{A}$, then the species is :

Question 21 :
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 22 :
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 23 :
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 25 :
Number of waves made by the pion when orbiting in third excitation state are