A free nucleus of mass $24$ u emits a gamma photon [when initially at rest]. The energy of the photon is $7$ MeV. The recoil energy of the nucleus in keV is 

Hydrogen atom will be in its ground state,if its electron is in

When writing electron configurations,electrons are represented in their lowest possible energy state.Which of the following state is this ?

A beam of ultraviolet radiation having wavelength between $100nm$ and $200nm$ is incident on a sample of atomic hydrogen gas. Assuming that the atoms are in ground state, which wavelengths will have low intensity in the transmitted beam? 

The ground state energy of the electron in hydrogen atom is equal to :

The total energy of an electron in the ground state of hydrogen atom is $-13.6\space eV$. The potential energy of an electron in the ground state of $Li^{2+}$ ion will be

The ground state energy of Hydrogen atom is $–13.6eV$. The potential energy of the electron in this state is:

In which of the following systems will the radius of the first orbit (n = 1) be minimum ?

What is energy released in the $\beta  - decay\;of{\;^{32}}P{ \to ^{32}}S?$(Given:atomic masses:31.97391 u for $\left( {^{32}P\;and\;31.97207\;u\;fo{r^{32}}S} \right)$

A sample originally contained $10 ^ { 20 }$radioactive atoms, which emit $\alpha$ -particles emitted inthe thirdyear to that emitted during the second year is $0.3 $.How many $\alpha$ particles were emitted in the first year?

Nuclei $X$ decay into nuclei $Y$ by emitting $\alpha$ particles. Energies of $\alpha$ particle are found to be only $1MeV$ & $1.4MeV$. Disregarding the recoil of nuclei $Y$. The energy of $\gamma$ photon emitted will be:

A $ _6C^{12} $ nucleus is to be divided into 3 alpha particles . the amount of energy required to achieve this ( mass of an alpha particle=4.00388 u ) is

A source of energy of 100 W is producing energy by fission of 1 Kg $U^{235}$. How long it can kept generation of energy :- 

The atomic masses of the hydrogen isotopes are
$m _1H^1=1.007825\ amu$
$m _1H^2=2.014102\ amu$
$m _1H^3=3.016049\ amu$
The energy released in the reaction
$ _1H^2+ _1H^2 \rightarrow _1H^3+ _1H^1$
is nearly:

A gamma ray photon creates an electron-positron pair. If the rest mass energy of an electron is $0.5MeV$ and the total kinetic energy of the electron-positron pair is $0.78 MeV$, then the energy of the gamma ray photon must be

A stationary nucleus of mass $24\ amu$ emits a gamma photon. The energy of the emitted photon is $7\ MeV$. The recoil energy of the nucleus is:

Consider the following nuclear reaction:
$X^{200}\rightarrow A^{110}+B^{90}+Energy$
If the binding energy per nucleon for $X$, $A$ and $B$ are $7.4\ MeV$, $8.2\ MeV$ and $8.2\ MeV$ respectively, the energy released will be:

In a $\gamma -$decay process, $\gamma-$rays of energy $E$ is emitted. Find the decrease in internal energy of mass $M$ (of nucleus).

Mark out the correct statement(s)

The wavelength of emitted $\gamma $ rays are in the other

A free nucleus of mass $24 amu$ emits a gamma photon (when initially at rest). The energy of the photon is $7 MeV$. The recoil energy of the nucleus in $keV$ is