Atoms And Nuclei - Modern Physics - Physics Previous Year Questions

If the series limit frequency of Balmer series is $v_B$, then the series limit frequency of the Brackett series is

Which of the following interaction is responsible for beta decay?

Consider a nucleus ${ }_{30}^{60} \mathrm{X}$. Its approximate density is (take, $1 \mathrm{amu}=1.6 \times 10^{-27} \mathrm{~kg}, R_0=1.2 \times 10^{-15} \mathrm{~m}$ )

As the mass number $A$ increases, which of the following quantities related to a nucleus does not change?

If $F_1$ and $F_2$ are the relative strengths of the gravitational and weak nuclear forces respectively, then $F_2 / F_1$ is nearly

In the following nuclear reaction $X$ is

$${ }_{13} \mathrm{Al}^{27}+{ }_2 \mathrm{He}^4 \longrightarrow{ }_0 n^1+X$$

The nucleus ${ }_{50}^{120} X$ undergoes the series of reactions given below:

$${ }_Z^A X \xrightarrow{\alpha \text {-decay }} P \xrightarrow{\beta^{-} \text {-decay }} Q \xrightarrow{\alpha \text {-decay }} R$$

The number of neutrons in the nucleus $R$ is

The radius of a nucleus of mass number 27 is $R$. Which of the following is true about a nucleus whose radius is $2 R$ ?

In hydrogen spectrum, the shortest and longest wavelengths of Balmer series are $\lambda_1$ and $\lambda_2$ respectively. The Rydberg constant of hydrogen is

$\alpha$-decay of a parent nucleus $X$ results in a daughter nucleus $Y$. If $m_x, m_y$ and $m_\alpha$ are the masses of the parent nucleus, the daughter nucleus and the $\alpha$-particles respectively, then the net kinetic energy gained in the process is

In the nuclear fission of one nucleus of $\mathrm{U}^{235}$ the energy released is 188 MeV . The energy released in the nuclear fission of 235 g of $\mathrm{U}^{235}$ is nearly

(Avogadro number $=6.02 \times 10^{23} \mathrm{~mol}^{-1}$ )

Energy released in the fission of a single uranium nucleus is 200 MeV . Then the number of fissions per second to produce 5 mW power is

The ratio of longest wavelengths of the spectral lines in the Lyman and Balmer series of hydrogen spectrum is

Half-life of a radioactive substance $A$ is two times the half-life of another radioactive substance $B$. Initially the number of nuclei of $A$ and $B$ are $N_A$ and $N_B$ respectively. After three half-lives of $A$, the number of nuclei of both are equal. Then $N_A / N_B$ is

Match the following.

(Take the relative strength of the strongest fundamental forces in nature as one)

Heavy water is used as moderator in nuclear reactor because

The ratio of the relative strengths of strong and weak nuclear forces is

In a hypothetical Bohr hydrogen atom, if the mass of the electron is doubled then the energy of the electron in the first orbit is