$A$ uniform rod of mass $M$ and length $L$ is placed on a smooth horizontal surface. $A$ horizontal force $F$ is applied at one end of the rod perpendicular to its length. The acceleration of the centre of mass of the rod is:

$A$ small fish $0.4\, m$ below the surface of a lake is viewed through a simple converging lens of focal length $3\, m$. The lens is kept at $0.2\, m$ above the water surface such that the fish lies on the optical axis of the lens. The image of the fish seen by the observer will be at (given $\mu_{water} = 4/3$):

What is $DDT$?

Which of the following reactions will $NOT$ occur with heated copper at $300\,^\circ C$?

$2 \ mol$ of zinc is dissolved in $HCl$ at $25 \ ^\circ C$. The work done in an open vessel is:

Which of the following vessels in a rabbit starts with capillaries and ends in capillaries?