Umakant Kondapure, Collin Fernandes, Nipun Bhatia, Vikram Bathula and, Ketki Deshpande Solutions for Chapter: Atoms, Molecules and Nuclei, Exercise 4: Evaluation Test

The average life time of a hydrogen atom excited to $n=2$ state is ${10}^{-8} \mathrm{s}$. The period of revolution of the electron on an average before it jumps to ground state is,

The binding energy per nucleon for ${}_1\mathrm{H}^2$ and  ${}_2\mathrm{He}^4$ are $1.1 \mathrm{MeV}$ and $7.1 \mathrm{MeV}$, respectively. The energy released when two ${}_1\mathrm{H}^2$ combine to form ${}_2\mathrm{He}^4$ is,

A hydrogen atom moves with a velocity $u$ and makes a head-on inelastic collision with another stationary hydrogen atom. Both atoms are in the ground state before collision. The minimum value of $u$ if one of them is to be given a minimum excitation energy is,

The magnetic moment by virtue of the orbital motion of an electron in an atom when orbital angular momentum is equal to one quantum unit is,

A material found within the body of an organism trapped in an iceberg had a ${}_6\mathrm{C}^{14}$ activity of about $0.144 \mathrm{Bq} {\mathrm{g}}^{-1}$. ${}_6\mathrm{C}^{14}$ activity of the living organism is $0.28 \mathrm{Bq} {\mathrm{g}}^{-1}$ and its half life $5730 \mathrm{years}$. The age of the organism would be,

Assertion: Ionisation energy of atomic hydrogen is greater than atomic deuterium.

Reason: Ionisation energy is proportional to reduced mass.

Transitions between three energy levels in a particular atom give rise to three spectral lines of wavelengths in increasing magnitude ${\lambda }_1\text{,} {\lambda }_2$ and ${\lambda }_3$. Which one of the following equations correctly relates ${\lambda }_1\text{,} {\lambda }_2$ and ${\lambda }_3$?

A beam of monochromatic light of wavelength $\lambda$ ejects photoelectrons from a caesium surface $\left({\mathrm{W}}_0=1.9 \mathrm{eV}\right)$ which are made to collide with hydrogen atoms in ground state. The maximum value of $\lambda$ for which hydrogen atoms may be ionised is

(Take value of $h=6.6\times {10}^{-34}$ in SI units)