Question 2 :
<div>State True or False.<br/></div>The velocity of the electron is maximum in the Bohr's last orbit.

Question 3 :
If r is radius of first orbit, the radius of nth orbit of the H atom will be :

Question 4 :
Energy of the electron in hydrogen in its first orbit is:

Question 5 :
The total energy of the electron revolving around the nucleus is:

Question 6 :
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 7 :
According to the Bohr model of the atom, which electron transition will emit the lowest energy photon?

Question 8 :
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 9 :
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 10 :
A particle of mass M at rest decays into two particles of masses $m1$ and $m_2$, havung non-zero velocities. The ratio of the de-Broglie wavelengths of the particles, $l_1/l_2$ is?

Question 11 :
If first ionisation energy of hydrogen is $E$, then the ionisation energy of ${ He }^{ + }$ would be:

Question 12 :
In an atom the shell which has a maximum two electrons is:

Question 13 :
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 14 :
Assertion: In an atom, the velocity of electron in the higher orbits keeps on decreasing. Reason: Velocity of electrons is inversely proportional to the radius of the orbit.

Question 15 :
<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 16 :
The quantum number n of the state finally populated in $He^{+}$ ions is&#160;<br/>

Question 17 :
The wavelength($\lambda_n$) of the pion orbiting in nth stationary state is given by

Question 19 :
The only electron in the hydrogen atom resides under ordinary conditions on the first orbit. When energy is supplied, the electron moves to higher energy orbit depending on the amount of energy absorbed. When this electron returns to any of the lower orbits, it emits energy. Lyman series is formed when the electron returns the lowest orbit while Balmer series is formed when the electron returns to the second orbit. Similarly, Paschen, Brackett, and Pfind series are formed when electron returns to the third, fourth, and fifth from higher orbits, respectively.<br/>Maximum number of lines produced when an electron jumps from &#160;nth level to ground level is equal to $\displaystyle\frac{n(n - 1)}{2}$.&#160;<br/><i></i>If the electron comes back from the energy level having energy E$_2$ to the energy level having energy E$_1$, then difference may be expressed in terms of energy of photon as<br/>E$_2$ - E$_1$ = $\Delta$E, $\lambda$ = hc/$\Delta$E<br/>Since h and c are constant, $\Delta$E corresponds to definite energy, thus, each transition from one energy level to another will produce a light of definite wavelength. This is actually observed as a line in the spectrum of hydrogen atom.<br/>Wave number of line is given by the formula<br/>v = $RZ^2\left( \displaystyle\frac{1}{n_1^2} - \frac{1}{n_2^2}\right)$<br/>where R is a Rydberg constant.The wave number of electromagnetic radiation emitted during the transition of electron in between the two levels of Li$^{2+}$ ion whose principal quantum numbers sum is 4 and difference is 2 is :

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

Question 22 :
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 23 :
Calculate the ratio of energies of $2^{nd}$ orbits of hydrogen, $He^+, Li^{+2}$.<br/>

Question 24 :
What is the energy required to move the electron from the ground state of H atom to the first excited state? Given that the ground state energy of H atom is 13.6 eV and that the energy E$_n$ of an electron in n$^{th}$ orbital of an atom or ion of atomic number Z is, given by the equation $E_n =(13.6Z^2/n^2)$

Question 25 :
If elements of quantum number greater than $'n'$ were not allowed, the number of possible elements in nature would have been