Which of the following is a copper-releasing $IUD$?

$A$ particle of mass $4 m$ explodes into three pieces of masses $m, m$ and $2 m$. The equal masses move along $X$-axis and $Y$-axis with velocities $4 ms^{-1}$ and $6 ms^{-1}$ respectively. The magnitude of the velocity of the heavier mass is

During the depression in freezing point experiment,an equilibrium is established between the molecules of

Dry distillation of calcium acetate and calcium formate forms:

Phytochrome is involved in: