Which of the following metals is a water pollutant and causes sterility in human beings?

Approximately $70\%$ of carbon dioxide absorbed by the blood will be transported to the lungs:

$A$ rod of length $L$ is held vertically on a smooth horizontal surface. The top end of the rod is given a gentle push. At a certain instant of time,when the rod makes an angle $\theta$ with the horizontal,the velocity of the $COM$ of the rod is $v_0$. The velocity of the end of the rod in contact with the surface at that instant is:

$A$ long straight wire along the $z$-axis carries a current $I$ in the negative $z$-direction. The magnetic vector field $\vec B$ at a point having coordinates $(x, y)$ in the $z = 0$ plane is

All the springs in figures $(a)$,$(b)$,and $(c)$ are identical,each having a force constant $K$. The mass attached to each system is $m$. If $T_a, T_b$,and $T_c$ are the time periods of oscillations of the three systems respectively,then:

The binding energy of deuteron is $2.2 \, MeV$ and that of ${}_2^4He$ is $28 \, MeV$. If two deuterons are fused to form one ${}_2^4He$ nucleus,then the energy released is ......... $MeV$.