Atoms practice · Mixed difficulty

A $100 \mathrm{eV}$ electron collides with a stationary helium ion $\left(\mathrm{He}^{+}\right)$in its ground state and excites to a higher level. After the collision, $\mathrm{He}^{+}$ions emits two photons in succession with wavelength $1085\mathop {\text{A}}\limits^ \circ$ and $304\mathop {\text{A}}\limits^ \circ$. Also the energy of the electron after the collision is $6 \times \ldots \ldots \mathrm{eV}$ (approximately). Given $\mathrm{h}=6.63 \times 10^{-34} \mathrm{Js}$.

The wavelength of the first line of Lyman series for hydrogen atom is equal to that of the second line of Balmer series for a hydrogen like ion. The atomic number $Z$ of hydrogen like ion is

An electron moving around the nucleus with an angular momentum $l$ has a magnetic moment

The number of different wave lengths may be observed in the spectrum from a hydrogen sample if the atoms are excited to fourth excited state is

Which of the following parameters is same for electron in all hydrogen like atoms and ions in their ground states?

A hydrogen atom moves with a velocity $u$ and makes a head on inelastic collision with another stationary $\mathrm{H}$-atom. Both atoms are in ground state before collision. The minimum value of $u$ if one of them is to be given a minimum excitation energy is

In hydrogen atom, when electron jumps from second to first orbit, then energy emitted is

An electron rotates in a circle around a nucleus having positive charge $\text{Ze}.$ Correct relation between total energy $\text{(E)}$ of electron to its potential energy $\text{(U)}$ is:

In Davisson and Germer experiment intensity of scattered beam of electron was maximum at $50^{\circ}$ scattering angle and at

The order of the size of nucleus and Bohr radius of an atom respectively are

The angular momentum of electron in ${n^{\mathrm{th}}}$ orbit is given by

$E_1$ is energy of $K_\alpha$ photon of aluminium, $E_2$ is energy of $K_\beta$ photon of aluminium and $E_3$ is energy of $K_\alpha$ photon from sodium, then the correct order of energies is given:

According to Bohr model, magnetic field at the centre (at the nucleus) of a hydrogen atom due to the motion of the electron in $n$th orbit is proportional to:

The transition of an electron from ${n_2} = 5,6, \ldots \ldots$ to ${n_1} = 4$ gives rise to

Assertion: For the scattering of $\alpha$-particles at large angles, only the nucleus of the atom is responsible.
Reason: Nucleus is very heavy in comparison to electrons.

The Rydberg constant $R$ for hydrogen is

In Bohr's theory for hydrogen-like atoms:

Taking the wavelength of first Balmer line in the hydrogen spectrum $(n=3$ ton $=2)$ as $660 \mathrm{~nm}$, then the wavelength of $2^{\text {nd }}$ balmer line in the same spectrum $(n=4$ ton $=2)$ will be

If the ionization potential of helium atom is 24.6 volt, the energy required to ionize it will be

The electron in a hydrogen atom makes a transition from an excited state to the ground state. Which of the following statements is true

In Davisson - Germer experiment maximum intensity is observed at

Intensity of $X$-rays depends upon the number of

Statement-I: In the experiment of alpha particle scattering, extremely thin gold foils are preferred over other metals.

Statement-II: Gold is a ductile material.

The wavelength of the first spectral line in the Balmer series of hydrogen atom is $6561\,\mathop \mathrm{A}\limits^ \circ$. The wavelength of the second spectral line in the Balmer series of singly ionized helium atom is

A moving hydrogen atom makes a head-on collision with another stationary hydrogen atom. Before collision both atoms are in their ground states, and after collision they move together. The mininum value of the kinetic energy of the moving hydrogen atom (in $\mathrm{eV})$, such that one of the atom reaches the 1st excited state will be:

The energy necessary to remove the electron from $n = 10$ state in hydrogen atom will be

In an $X$-rays tube, the intensity of the emitted $X$-rays beam is increased by

The angular momentum of electron is J. Its magnetic moment will be

The maximum number of photons emitted by an H-atom, if atom is excited to states with principal quantum number four is

Which of the following statements about the Bohr model of the hydrogen atom is false