Structure of atom practice · Mixed difficulty

The energy ∆E corresponding to intense yellow line of sodium of $\lambda ,\;589\;\mathrm{nm}$ is 

Millikan’s oil drop experiment is used to find:

An electron from one Bohr stationary orbit can go to next higher orbit

Which one of the following groupings represents a collection of isoelectronic species? (At. no. Cs=55, Br=35)

Particle having mass 200 times that of an electron is:

The species having more electrons than neutrons is:

Photoelectric effect was discovered by :

Which of the following options is incorrect regarding Bohr’s model of an atom

The ratio of specific charges of $\alpha$-particle and deuteron is

Statement - I: For Hydrogen spectrum all Balmer lines in the emission spectrum have longer
wavelengths than that of any line of Lyman series.

Statement - II: Transition energy is always greater when electrons come to an orbit with
lower orbit number than an electron come to an orbit with higher orbit number, irrespective to
higher orbit from which electron is coming.

In Bohr's model of the hydrogen atom the ratio between the period of revolution of an electron in the orbit n=1 to the period of revolution of the electron in the orbit n=2 is:

$\alpha$-particles can be detected by using

Density of the electron is:

The statements, which is/are correct:

What accelerating potential is needed to produce an electron beam with an effective wavelength of $0.090$?

Which one of the following ions is not isoelectronic with ${\mathrm{O}^{2 - }}?$

The principal quantum number n can have integral values ranging from:

Isotopes have

The electronic configuration $1{s^2},2{s^2}2{p^6},3{s^1}3{p^1}$ correctly describes:

The frequency of first line of Balmer series in hydrogen atom is ${v_0}$. The frequency of corresponding line emitted by singly ionised helium atom is :

The energy of an electron in Bohr's orbit of hydrogen atom is $-13.6 \mathrm{~eV}$. The total electronic energy of a hypothetical $\mathrm{He}$ atom in which there are no electron-electron repulsions or interactions is

${I_2}$ molecule dissociates into atoms after absorbing light of 4500 A°. If one quantum of energy is absorbed by each molecule, the KE of iodine atoms will be (BE of ${\mathrm{I}_2} = 240\,\,kJ/mol$ )

The wavelength of shortest wavelength transition in Lyman series of atomic Hydrogen is

The first orbital of H is represented by :$\mathrm{\psi } = \frac{1}{{\sqrt \mathrm{\pi } }}{\left( {\frac{1}{{{\mathrm{a}_0}}}} \right)^{3/2}}{\mathrm{e}^{ - \mathrm{r}/{\mathrm{a}_0}}},$ , where ${a_0}$ is Bohr's radius. The probability of finding the electron at a distance r, from the nucleus in the region dV is:

The velocities of two particles A and B are 0.05 and 0.02 $\;\mathrm{m}{\mathrm{s}^{ - 1}}$ respectively. The mass of B is five times the mass of A. The ratio of their de-Broglie’s wavelength is

The atomic number of the element having maximum number of unpaired 3p-electrons is:

The electron in the hydrogen atom is excited to the 4th orbit. Number of spectral lines expected in the emission is

Which relates to light only as stream of particles?

What should be the mass of the sodium photon if its wavelength is $5894 \, \overset{\circ }{\mathop{\text{A}}}\,,$ the velocity of light is $3 \times 10^8$ metre/second and the value of $\text{h}$ is $6.652 \times 10^{-34} \mathrm{~kg} \mathrm{~m}^2 / \mathrm{sec}?$

If the shortest wavelength of H-atom in Lyman series is x, the longest wavelength in Balmer series of $\mathrm{H}{\mathrm{e}^ + }$ is