The uncertainty in the velocities of two particles $A$ and $B$ are 0.03 and $0.01 \mathrm{~ms}^{-1}$ respectively. The mass of $B$ is four times to the mass of $A$. The ratio of uncertainties in their positions is

The total maximum number of electrons possible in $3 d$. $6 d, 5 s$ and $4 f$ orbitals with $m_l$ (magnetic quantum number) value -2 is

The radius of fourth orbit in $\mathrm{He}^{+}$ion is ' $R_1{ }^{\prime} \mathrm{pm}$ and radius of third orbit in $\mathrm{Li}^{2+}$ ion is ' $R_2{ }^{\prime} \mathrm{pm}$. The value of ( $R_1-R_2$ ) in pm is

The de-Broglie wavelengths of two fast moving particles $X, Y$ are $1 \mathrm{~nm}, 3 \mathrm{~nm}$ respectively. Mass of $X$ is nine times the mass of $Y$. The ratio of kinetic energies of $X, Y$ is