The graph that correctly represents the relation of frequency v of a particular characteristic X-ray with the atomic number Z of the material is

If in nature there may not be an element for which the principal quantum number n > 4, then the total possible number of elements will be

In the n^th orbit, the energy of an electron is ${\mathrm{E}}_{\mathrm{n}}=-\frac{13.6}{{\mathrm{n}}^2}\mathrm{eV}$ for the hydrogen atom. The energy required to take the electron from the first orbit to the second orbit will be:

The Lyman series of hydrogen spectrum lies in the region

Which one of the series of hydrogen spectrum is in the visible region 

The Rutherford $\mathrm{\alpha }$-particle experiment shows that most of the $\mathrm{\alpha }$-particles pass through almost unscattered while some are scattered through large angles. What information does it give about the structure of the atom 

Which of the following is true 

The energy required to knock out the electron in the third orbit of a hydrogen atom is equal to

An electron has a mass of $9.1\times {10}^{-31} \mathrm{kg}$. It revolves round the nucleus in a circular orbit of radius $0.529\times {10}^{-10}$ metre at a speed of $2.2\times {10}^6 \mathrm{m}/\mathrm{s}$. The magnitude of its linear momentum in this motion is

The ionization potential for second He electron is

The energy required to remove an electron in a hydrogen atom from n = 10 state is 

Every series of hydrogen spectrum has an upper and lower limit in wavelength. The spectral series which has an upper limit of wavelength equal to 18752 Å is 

(Rydberg constant R = $1.097\times {10}^7$ per metre)

An electron jumps from the 4th orbit to the 2nd orbit of hydrogen atom. Given the Rydberg's constant R = ${10}^5 {\mathrm{cm}}^{-1}$. The frequency in Hz of the emitted radiation will be 

The ionisation potential of hydrogen atom is 13.6 volt. The energy required to remove an electron in the n = 2 state of the hydrogen atom is 

A beam of fast moving alpha particles were directed towards a thin film of gold. The parts A', B', and C' of the transmitted and reflected beams corresponding to the incident parts A, B and C of the beam, are shown in the adjoining diagram. The number of alpha particles in

If m is mass of electron, v its velocity, r the radius of stationary circular orbit around a nucleus with charge Ze, then from Bohr's first postulate, the kinetic energy $\mathrm{K}=\frac{1}{2}{\mathrm{mv}}^2$ of the electron in C.G.S. system is equal to

The electron in a hydrogen atom makes a transition from an excited state to the ground state. Which of the following statements is true 

Figure shows the energy levels P, Q, R, S and G of an atom where G is the ground state. A red line in the emission spectrum of the atom can be obtained by an energy level change from Q to S. A blue line can be obtained by following energy level change 

A hydrogen atom (ionisation potential 13.6 eV) makes a transition from third excited state to first excited state. The energy of the photon emitted in the process is 

The figure indicates the energy level diagram of an atom and the origin of six spectral lines in emission (e.g. line no. 5 arises from the transition from level B to A). The following spectral lines will also occur in the absorption spectrum

An electron in the n = 1 orbit of hydrogen atom is bound by 13.6 eV. If a hydrogen atom is in the n = 3 state, how much energy is required to ionize it 

Which of the following statements about the Bohr model of the hydrogen atom is false 

The ratio of the frequencies of the long wavelength limits of Lyman and Balmer series of hydrogen spectrum is

Which of the following transitions in a hydrogen atom emits photon of the highest frequency

Which of the transitions in hydrogen atom emits a photon of lowest frequency (n = quantum number)

According to Bohr's theory, the expressions for the kinetic and potential energy of an electron revolving in an orbit is given respectively by

The absorption transitions between the first and the fourth energy states of hydrogen atom are 3. The emission transitions between these states will be 

The ratio of longest wavelength and the shortest wavelength observed in the five spectral series of emission spectrum of hydrogen is 

In Bohr's model of hydrogen atom, let PE represents potential energy and TE the total energy. In going to a higher level 

 According to Bohr's model, the radius of the second orbit of helium atom is