Structure of atom practice · Mixed difficulty

Bohr’s radius of 2nd orbit of $\mathrm{B}{\mathrm{e}^{3 + }}$ is equal to that of

The magnetic moment of a particular ion is $2 \sqrt{6}$ $B.M.$ The ion is

A bulb emits light of $\lambda=4500 ~\mathop {\text{A}}\limits^ \circ$. The bulb is rated as 150 watt and $8 \%$ of the energy is emitted as light. How many photons are emitted by the bulb per second?

The wavelength (in cm) of second line in the Lyman series of hydrogen atomic spectrum is

An electron moves around the nucleus in a circle of radius $r$. Assuming that the uncertainty of the momentum of electron is of the same order as momentum itself, the momentum of the electron would be

According to Bohr's postulates which quantity can take up only discrete values:

The work-function for photoelectric effect :

The total number of orbitals possible for principle quantum number n is

The number of d-electrons retained in $\mathrm{F}{\mathrm{e}^{2 + }}$(At. No. Fe=26) ions is

The five $d$-orbitals are designated as $d_{x y}, d_{y z}, d_{x z}, d_{x^2-y^2}$ and $d_{z^2}$. Choose the correct statement.

The mass defect of the nuclear reaction: ${ }_5 {B}^8 \rightarrow{ }_4 {Be}^8+{e}^{+}$is

Thewavelength of a $150 \mathrm{~g}$ rubber ball moving with a velocity of $50 {~ms}^{-1}$ is :

Which one of the following sets of ions represents a collection of iso electronic species

Which of the following combination of quantum number is allowed

The threshold energy is given as ${E_0}$ and radiation of energy $E$ falls on metal, then K.E is given as

Which of the following does not represent the mathematical expression for the Heisenberg uncertainty principle.

The atomic weight of an element is double of its atomic number. If there are four electrons in $2 p$ orbital, the element is isotonic with

Many types of electromagnetic radiations, differ from one another in wavelength (or frequency) constitute a spectrum known as

Statement-I : The K.E of photo electrons depend on energy and frequency of incident light
Statement-II : The number of photo electrons emitted depend on intensity of incident light

Arrange the following in terms of penetrating power. $\alpha$-rays, $\beta$-rays, $\gamma$-rays

In a sample of hydrogen atoms, all the atoms are in a particular excited state. If the emission spectrum of this sample has only 4 spectral lines in the visible region, then the total number of spectral lines in IR region possible from that state is

If the ratio of radii of two shells of a $\mathrm{H}$-like species is $25: 64$, then the ratio of the velocities will be

Which of the following levels of ${H}$ and ${He}^{+}$have same energy respectively ?

(A) 1,2

(B) 3,4

(C) 2, 4

(D) 3,6

Which quantum number is not related with Schrodinger equation

The orbital angular momentum for an electron revolving in an orbit is $\frac{h}{{2\pi }}\sqrt {l\left( {l + 1} \right)} .$. Thus momentum for a s-electron is:

A golf ball has a mass of 40 g and a speed of 45 m/s. It the speed can be measured within accuracy of 2% the uncertainity in the position is

Consider the following statements obtained after solving the Schrodinger equation for hydrogen atom,

I. we get the possible energy levels that the electron can occupy.

II. the atomic orbital is the wave function $(\psi)$ for an electron in an atom.

The correct statement(s) is/are

Statement (S): $d$-orbitals are five fold non-degenerate in presence of magnetic field.

Explanation (E): In presence of magnetic field the energy of orbitals becomes altogether different.

A photon of radiation of wavelength $4000 ~\mathop {\text{A}}\limits^ \circ$ has an energy $E$. The wavelength of photon of radiation having energy $0.5 E$ will be

Which has minimum number of unpaired d-electrons?