Taking the Bohr radius as a₀ = 53pm, the radius of Li⁺⁺ ion its ground state, on the basis of Boh''s model, will be about

The Bohr model for the spectre of a H-atom

Two H atoms in the ground state collide inelastically. The maximum amount by which their combined kinetic energy is reduced is

In a hydrogen atom, if the electron is replaced by a particle which is 200 times heavier but has the same charge, how would its radius change?

Define ionisation energy. How would the ionisation energy change when electron in hydrogen atom is replaced by a particle 200 times heavier than electron, but having the same charge?

Assuming the nuclei to be spherical in shape, how does the surface area of a nucleus of mass number \({ A }_{ 1 }\) compare with that of a nucleus of mass number \({ A }_{ 2 }\)?

What is the effect on neutron to proton ratio in a nucleus when (i) an electron, (ii) a positron is emitted?

Calculate the energy equivalent of 1 a.m.u. in MeV.

(a) Using the Bohr's model, calculate the speed of the electron in a hydrogen atom in the n = 1, 2, and 3 levels
(b) Calculate orbital period in each of these levels.

In the Auger process an atom makes a transition to a lower state without emitting a photon.the excess energy is transferred to an outer electron which may be ejected by the atom.(This is called an Auger electron).Assuming the nucleus to be massive, calculate the kinetic energy of an n = 4 Auger electron emitted by Chromium by absorbing the energy from a n = 2 to n = 1 transition.

Einstein was the first to establish the equivalence between mass energy. According to him, whenever a certain mass \(\left( \Delta m \right) \) disappears in some process, the amount of energy released is \(E=\left( \Delta m \right) { c }^{ 2 },\) where c is velocity of light vacuum \(\left( =3\times { 10 }^{ 8 }m/s \right) .\) The reverse is also true, i.e., whenever energy E disappears, an equivalent mass \(\left( \Delta m \right) ={ E/c }^{ 2 }\) appears.
Read the above passage and answer the following questions :
(i) What is the energy released when 1 a.m.u. of mass disappears in a nuclear reaction?
(ii) Do you know any phenomenon in which energy materialises?
(iii) What values of life do you learn from this famous relation?

According to Bohr's theory of hydrogen atom, total energy of electron in a stationary orbit is \(E=-\frac { 13.6 }{ { n }^{ 2 } } eV,\) where n is the number of orbit. Clearly, total energy of electron in a stationary orbit is negative, which means the electron is bound to the nucleus and is not free to leave it. An n increases, value of negative energy decreases, i.e., energy is progressively larger in the outer orbits.
Read the above passage and answer the following questions :
(i) What is total energy of electron in ground state of hydrogen atom? What does it imply?
(ii) Energy required to remove an electron is smaller when atoms is in any one excited state. Comment.
(iii) How is this concept translated in day to day life?

Marie Curie and her teacher turned husband Pierre Curie worked hard to extract radium chloride (R_aCl₂) from uranium ore. They succeeded in 192 after a long struggle. About 0.19 g of R_aCl₂ was extracted and its radioactivity was studied. They were awarded by the noble prize, which they shared it which they shared it which they shared it with Henri Becquerel.
Read the above passage and answer following questions:
(i) What are the values shown by Marie Curie and her husband?
(ii) What do you understand by radioactivity? How the half-life period is related to the disintegration constant?
(iii) How is average-life of radioactive element related to half-life?