Which process is used to obtain products like cheese and yogurt?

Which substance is used as a smoke screen in warfare?

In a hydrogen-like atom,an electron makes a transition from an energy level with quantum number $n$ to another with quantum number $(n - 1)$. If $n >> 1$,the frequency of the emitted radiation is proportional to:

Which insect is used to control the spread of prickly pear cactus $(Opuntia)$?

The area (in sq unit) of the region bounded by the curves $2x = y^2 - 1$ and $x = 0$ is

The centre of mass of a body