Developments Leading to the Bohr'S Atomic Model

The energies  ${\mathrm{E}}_1\mathrm{and}{\mathrm{E}}_2$  of two radiations are $25 \mathrm{eV}$ and $50 \mathrm{eV}$, respectively. The relation between their wavelength i.e.,  ${\mathrm{\lambda }}_1\mathrm{and}{\mathrm{\lambda }}_2$ will be:

The value of Planck’s constant is  $6.63\times {10}^{-34}Js.$  The velocity of light is  $3.0\times {10}^{8}m{s}^{-1}.$  Which value is closest to the wavelength in meters of a quantum of light with frequency of  $8\times {10}^{16}{s}^{-1}?$

What leads to the establishment of the particle nature of electron?

The wavelength of a particular radiation is $700 \mathrm{nm}\left(1\mathrm{nm}={10}^{-9}\mathrm{m}\right)$. Find its frequency $\left(\mathrm{\vartheta }\right)$. 

On what basis did Bohr propose his atomic model? 

Give the value of Planck's constant in $\mathrm{joule}.\sec$.

Give the value of Planck's constant in $\mathrm{erg}.\sec$. 

Which theory supported the particle nature of an electron? 

What name did Max Planck give to energy packets?

What was the mathematical equation given by Max Planck? 

The number of following statement/s which is/are incorrect is ______

A) Line emission spectra are used to study the electronic structure

B) The emission spectra of atoms in the gas phase show a continuous spread of wavelength from red to violet.

C) An absorption spectrum is like the photographic negative of an emission spectrum

D) The element helium was discovered in the sun by spectroscopic method

Values of work function $\left({\mathrm{W}}_0\right)$ for a few metals are given below

The number of metals which will show photoelectric effect when light of wavelength $400 \mathrm{nm}$ falls on it is _____

Given: $h=6.6\times {10}^{–34} \mathrm{J} \mathrm{s}$

$c=3\times {10}^8 {\mathrm{ms}}^{–1}$

$e=1.6\times {10}^{–19} \mathrm{C}$

Potential energy of an electron is defined as $U=\frac{1}{2}m{\omega }^2{x}^2$ and follows Bohr's law. Radius of orbit as function of $n$ depends on

Bohr model is applied to a particle of mass $m$ and charge $q$ moving in a plane under the influence of a transverse magnetic field $B$. The energy of the charged particle in the$nth$ level will be

The wavelength of first line of Paschen series is $\mathrm{\lambda }=720 \mathrm{nm}$. The wavelength of $2\mathrm{nd}$ line of this series is ____.