Question
An electron collides with a free molecule initially in its ground state. The collision leaves the molecule in an excited state that is metastable and does not decay to the ground state by radiation. Let $K$ be the sum of the initial kinetic energies of the electron and the molecule and $p$ be the sum of their initial momenta. Let $K^{\prime}$ and $p ^{\prime}$ represent the same physical quantities after the collision. Then,

Answer

(b)

Part of kinetic energy of incoming electron is absorbed by molecule and it gets into excited state.

So, kinetic energy after collision is reduced (collision is inelastic).

Linear momentum is conserved as momentum conservation holds correct for elastic as well as inelastic collision.

So, $\quad K^{\prime} < K$ and $p ^{\prime}= p$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A plane electromagnetic wave of frequency $25\; \mathrm{GHz}$ is propagating in vacuum along the $z-$direction. At a particular point in space and time, the magnetic field is given by $\overrightarrow{\mathrm{B}}=5 \times 10^{-8} \hat{\mathrm{j}}\; \mathrm{T}$. The corresponding electric field $\overrightarrow{\mathrm{E}}$ is (speed of light  $\mathrm{c}=3 \times 10^{8}\; \mathrm{ms}^{-1})$
Two insulated metallic spheres of $3\,\mu F$ and $5\,\mu F$ capacitances are charged to $300\, V$ and $500\, V$ respectively. The energy loss, when they are connected by a wire is
The resultant of two forces $3P$ and $2P$ is $R$. If the first force is doubled then the resultant is also doubled. The angle between the two forces is  ........... $^o$
Parallel rays of light of intensity $I =912 \ Wm ^{-2}$ are incident on a spherical balck body kept in surroundings of temperature $300 \ K$. Take Stefan-Boltzmann constant $\sigma=5.7 \times 10^{-8} Wm ^{-2} K ^{-4}$ and assume that the energy exchange with the surroundings is only through radiation. Th final steady state temperature of the black body is close to:
The potential energy of a particle of mass $1\, kg$ in motion along the $x-$ axis is given by $U = 4\,(1 -cos\,2x)$, where $x$ is in $metres$ . The period of small oscillation (in $second$ ) is
Aball is thrown from a point on ground at some angle of projection. At the same time a bird starts from a point directly above this point of projection at a height $h$ horizontally with speed $u$. Given that in its flight ball just touches the bird at one point. Find the distance on ground where ball strikes
Two vessels of the same volume contain the same gas at same temperature. If the pressure in the vessels be in the ratio of $1 : 2$, then
Two coils of self inductance $2\,\,mH$ and $8\,\,mH$ are placed so close together that the effective flux in one coil is completely linked with the other. The mutual inductance between these coils is......$  mH$
If wire of length $L$ form a loop of radius $R$ and have $n$ turn. Find magnetic field at centre of loop if current flowing in loop is $I$
Water is used to cool radiators of engines, because