Structure of atom practice · Mixed difficulty

Which has the highest number of unpaired electrons?

The number of electrons in the nucleus of ${C^{12}}$ is

Maximum number of electrons in an orbit is given by:

What is the minimum energy that photons must posses in order to produce photoelectric effect with platinum metal? The threshold frequency for platinum is $1.3 \times {10^{15}}{s^{ - 1}}$

The ratio of slopes of $K_{\max } v s . v$ and $V_0 v s . v$ curves in the photoelectric effect gives $(v=$ frequency, $K_{\max }=$ maximum kinetic energy, $V_0=$ stopping potential) :

During photoelectric effect, the kinetic energy of the electron ejected from metal surface depends on

An orbital in which $n = 4\;\mathrm{and}\;l = 2$ is expressed by

For the Balmer series in the spectrum of $H$ atom, $\overline v = {R_H}\left\{ {\frac{1}{{n_1^2}} - \frac{1}{{n_2^2}}} \right\}$ the correct statements among (I) to (IV) are :
(I) As wavelength decreases, the lines in the series converge
(II) The integer ${n_1}$ is equal to
(III) The lines of longest wavelength corresponds to ${n_2} = 3$
(IV) The ionisation energy of hydrogen can be calculated from wave number of these lines

The values of four quantum numbers of valence electron of an element are $n = 4,\;l = 0,\;m = 0\;\mathrm{and}\;s = + \frac{1}{2}\;$ The element is

An atom has net charge of -1. It has 18 electrons and 20 neutrons. Its mass number is:

H has two natural isotopes of $_1{\mathrm{H}^1}$ and $_1{\mathrm{H}^2}$ and O has two isotopes $\mathrm{\;}\,{O^{16}}$ and $\mathrm{\;}\,{O^{18}}$. Which of the following mol.wt.of ${H_2}O$ will not be possible?

Energy of H-atom in the ground state is -13.6 eV, hence energy in the second excited state is

Which of the following has more number of unpaired electron?

The total spin for atoms with atomic number 7,24,34 and 36 will be

A particular station of All India Radio, New Delhi broadcasts on a frequency of 1,368 kHz (kilohertz). The wavelength of the electromagnetic radiation emitted by the transmitter is: [speed of light $\mathrm{c} = 3.0 \times {10^8}\mathrm{ m}{\mathrm{s}^{ - 1}}$ ]

The work-function for photoelectric effect :

A hydrogen atom in its ground state absorbs a photon. The maximum energy of such a photon is:

Stark effect refers to the

Which wavelength falls in a X-rays region?

If uncertainty in position and momentum are equal, then uncertainty in velocity is:

Atomic radius is of the order of ${10^{ - 8}}\mathrm{cm}$ cm and nuclear radius of the order of ${10^{ - 13}}\mathrm{cm}$. The fraction of atom occupied by nucleus is:

Gamma rays are:

The dynamic mass of a photon of wavelength $\lambda$ is

The wavelength of radiation emitted when electron falls from 4th Bohr's orbit to 2nd in H-atom is: $\left( {{R_\mathrm{H}} = - 1.09678 \times {{10}^{ - 7}}{\mathrm{m}^{ - 1}}} \right)$

The energy ration of a photon of wavelength 3000 Å and 6000Å is

Bohr frequency condition is given by

Photons of energy 6 eV are incidented on a potassium surface of work function 2.1 eV. What is the stopping potential?

Which of the following statements does not form a part of Bohr’s model of hydrogen atom?

Which of the following electron transition in hydrogen atom will require largest amount of energy?

Which of the following statement is incorrect regarding the oil droplets experiment?