Structure of atom practice · Medium

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 work-function for photoelectric effect :

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

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

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

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.

The atomic number of an element is 35 and its mass is 81. The number of electrons in its outermost shell is

The radius of first orbit of $\mathrm{H}$-atoms is $0.529\mathop {\text{A}}\limits^ \circ$. The radius of first orbit of $\mathrm{D}$-atoms should be

In unielectron system, the wave number of any spectral line is directly proportional to

If ${S_1}$ be the specific charge (e/m) of cathode ray and ${S_2}$ be that of positive rays, then which is true?

Cathode rays carry/are

A 100 watt bulb emits monochromatic light of wavelength 400 nm, the number of photons emitted per second by this bulb is

Magnetic moments of $V(Z=23), \operatorname{Cr}(Z=24)$ and $\operatorname{Mn}(Z=25)$ are $x, y, z$. Hence

Which of the following sets of quantum numbers is correct for an electron in 4f-orbital.

A quantity of $1.0 \mathrm{~g}$ hydrogen atoms are excited to radiations. The study of spectra indicates that $45 \%$ of the atoms are in third energy level and $40 \%$ of atoms in second energy level and the rest in ground state. The total energy (in $\mathrm{kJ}$) evolved, when all the atoms return to ground state is (Ionization energy of hydrogen atom is $1310 \mathrm{~kJ} / \mathrm{mol}$)

The uncertainty in position and velocity of a particle are $10^{-11} \mathrm{~m}$ and $5.27 \times 10^{-24} \mathrm{~ms}^{-1}$, respectively. The minimum mass of the particle (in $\mathrm{kg}$ ) is

If Rutherford would have used $\beta$-particles instead of $\alpha$-particles in his Gold-leaf experiment, which of the following observations would definitely not have been made:

Which set of quantum number are not possible

A 25 Watt bulb emits monochromatic yellow light of wavelength of $0.57 \mu \mathrm{m}$. What will be the rate of emission of quanta per second?

Total number of spectral lines in UV region, during transition from $5^{\text {th }}$ excited state to $1^{\text {st }}$ excited state