NEET Physics MCQs

The ionization energy of hydrogen is 13.6 eV. Express this energy in joules per mole using the following conversions: 1 eV = $1.602 imes 10^{-19}$ J and Avogadro's number = $6.022 imes 10^{23}$ $mol^{-1}$.

A molecule of a substance has a permanent electric dipole moment of magnitude $10^{-29} \mathrm{~cm}.$ 2 mole of this substance is polarized (at low temperature) by applying a strong electrostatic field of magnitude $10^6 \mathrm{~Vm}^{-1}.$ What should be potential energy of its?

[1 mole of the substance contains $6 imes 10^{23}$ molecules]

Assuming the mass of Earth as $6.64 imes {10^{24}}kg$ and the average mass of the atoms that make up earth as 40u (atomic mass unit), the number of atoms in the Earth are approximately

The volume occupied by 8gm of oxygen at S.T.P is

The gas in vessel is subjected to a pressure of 20 atmosphere at a temperature ${27^ \circ }C.$ The pressure of the gas in a vessel after one half of the gas is released from the vessel and the temperature of the remainder is raised by ${50^ \circ }C$ is

The pressure and temperature of an ideal gas in a closed vessel are $720\;kPa$ and ${40^ \circ }C$ respectively. If $\frac{1}{4}$ th of the gas is released from the vessel and the temperature of the remaining gas is raised to ${353^ \circ }C,$, the final pressure of the gas is

At NTP, sample of equal volume of chlorine and oxygen is taken. Now ratio of no. of molecules is

The density of copper is $9\,\, imes \,\,{10^3}\,\,{\rm{kg}}/{{\rm{m}}^3}$ and its atomic mass is ${\rm{63}}{\rm{.5}}\,\,{\rm{u}}$. Each copper atom provides one free electron. Estimate the number of free electrons per cubic metre in copper.