Umakant Kondapure, Collin Fernandes, Nipun Bhatia, Vikram Bathula and, Ketki Deshpande Solutions for Chapter: Atoms, Molecules and Nuclei, Exercise 2: Critical Thinking

In Bohr's model of hydrogen atom, the period of revolution of the electron in any orbit is proportional to
 

The energy of the lowest level of a hydrogen atom is $-13.6 \mathrm{eV}\text{.}$ The energy of the photon emitted in the transition from $n=3$ to $n=1$ is
 

The ionisation potential of the hydrogen atom is $13.6 \mathrm{eV}\text{.}$ Hydrogen atom in the ground state is excited by monochromatic radiation of photon energy $12.1 \mathrm{eV}$. The number of spectral lines emitted by hydrogen atoms according to Bohr's theory will be
 

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
 

If the binding energy per nucleon of deuteron is $1.115\mathrm{MeV}$. Its mass defect in atomic mass unit is
 

Two samples $\mathrm{X}$ and $\mathrm{Y}$ contain equal amounts of radioactive substances. If $\frac{1}{16}$th of the sample $\mathrm{X}$ and $\frac{1}{256}$th of the sample $\mathrm{Y}$ remain after $8$ hours, then the ratio of half-periods of $\mathrm{X}$  and $\mathrm{Y}$ is
 

Assertion: Natural radioactive nuclei are nuclei of high mass number.

Reason: The B.E. per nucleon of heavy nuclei is large as compared to that of the stable nuclei.

Rutherford assumed in his atomic model that