Which of the following substances releases nitrogen gas upon thermal decomposition?

In which of the following properties do the two enantiomers of lactic acid differ from each other?

If the circle $x^2+y^2+6x-2y+k=0$ bisects the circumference of the circle $x^2+y^2+2x-6y-15=0$,then $k$ is equal to

If $\sin A + \sin B = \sqrt{3}(\cos B - \cos A)$,then $\sin 3A + \sin 3B$ is equal to:

In a Young's double slit experimental arrangement shown here, if a mica sheet of thickness $t$ and refractive index $\mu$ is placed in front of the slit $S_1$, then the path difference $(S_1P - S_2P)$

$A$ balloon with mass $m$ is descending down with an acceleration $a$ (where $a < g$). How much mass should be removed from it so that it starts moving up with an acceleration $a$?