In the nuclear process, \({}_{11}^{22}Na \rightarrow {}_{10}^{22}Ne + e^{+} + X\), then \(X\) is
neutrino
Mass number 22 → 22 and atomic number 11 → 10 + 1 are already balanced by Ne and the positron, so \(X\) has no charge and no mass number.
In \(\beta^{+}\) decay a proton changes as \(p \rightarrow n + e^{+} + \nu\).
Lepton number is conserved only if the positron (an antilepton) is accompanied by a neutrino, so \(X = \nu\).
Hence, neutrino.
Similar Questions
In a semiconductor crystal, the total number of electrons in the outer shell is 4N. At absolute zero, the number of energy states of valence and conduction band are respectively
The angular momentum of the electron revolving in 2nd orbit is
If a particle is moving with a momentum of \((2\times10^{10})h\) kg m s-1 then the de Broglie wavelength associated with it (in angstrom) is (where h is Planck’s constant)
Energy equivalent of mass 0.5 kg is
The donor level in an \(n\)-type semiconductor lies
In a Germanium crystal containing N atoms, the total number of outer electrons in the crystal is
If a radioactive element disintegrates for a period of time equal to its mean life, then the fraction of the original amount remaining undisintegrated is
In the following nuclear reaction, Z is a/an
\({}_{80}^{197}X \rightarrow {}_{79}^{197}Y + Z + v\)
The ratio of the respective de Broglie wavelengths of two particles with kinetic energy of 0.02 eV and 2 eV, respectively, is
The plot of maximum kinetic energy of photo-electrons to the energy of the incident photon above its threshold frequency on a photo-sensitive material of work function \(\varphi\) is
Important Questions from Modern Physics
- A voltage regulating circuit consisting of Zener diode, having break-down voltage of 10 V and maximum power dissipation of 0.4 W, is operated at 15 V. The approximate value of protective resistance in this circuit is ______ $\Omega$.
- A particle having electric charge $3 \times 10^{-19}\text{ C}$ and mass $6 \times 10^{-27}\text{ kg}$ is accelerated by applying an electric potential of $1.21\text{ V}$. Wavelength of the matter wave associated with the particle is $\alpha \times 10^{-12}\text{ m}$. The value of $\alpha$ is __________. (Take Planck's constant $= 6.6 \times 10^{-34}\text{ J.s}$)
- The average energy released per fission for the nucleus of ${}^{235}_{92}\text{U}$ is $190 \text{ MeV}$. When all the atoms of $47 \text{ g}$ pure ${}^{235}_{92}\text{U}$ undergo fission process, the energy released is $\alpha \times 10^{23} \text{ MeV}$. The value of $\alpha$ is ________.
(Avogadro Number = $6 \times 10^{23} \text{ per mole}$) - The energy released when $\frac{7}{17.13} \text{ kg}$ of ${}^7_3\text{Li}$ is converted into ${}^4_2\text{He}$ by proton bombardment is $\alpha \times 10^{32} \text{ eV}$. The value of $\alpha$ is _________. (Nearest integer)
(Mass of ${}^7_3\text{Li} = 7.0183 \text{ u}$, mass of ${}^4_2\text{He} = 4.004 \text{ u}$, mass of proton = $1.008 \text{ u}$ and $1 \text{ u} = 931 \text{ MeV/}c^2$ and Avogadro number $= 6.0 \times 10^{23}$) - A nuclear physicist performed an experiment on the scattering of alpha particles by thin metal foil of gold. The alpha particles were accelerated up to kinetic energy $3.2$ Mev. The estimation of the radius of the nucleus of gold element $(Z = 79)$ by him is $\times 10^{-16}$ m
(Take $\frac{1}{4\pi \epsilon_0} = 9\times10^9 \frac{Nm^2}{C^2}$)
