$A$ body cools from $62^{\circ}C$ to $50^{\circ}C$ in $10 \text{ minutes}$ and to $42^{\circ}C$ in the next $10 \text{ minutes}$. The temperature of the surroundings is ........ $^{\circ}C$.

The sum of the solutions of the equation $|\sqrt{x}-2|+\sqrt{x}(\sqrt{x}-4)+2=0$ for $x>0$ is equal to:

Companion cells in plants are associated with

$A$ solution which is $10^{-3} \ M$ each in $Mn^{2+}$,$Fe^{2+}$,$Zn^{2+}$ and $Hg^{2+}$ is treated with $10^{-16} \ M$ sulphide ion. If the $K_{sp}$ of $MnS$,$FeS$,$ZnS$ and $HgS$ are $10^{-15}$,$10^{-23}$,$10^{-20}$ and $10^{-54}$ respectively,which one will precipitate first?

What is the maximum number of rectangular components into which a vector can be split in space?

In the given circuit,find the equivalent resistance between points $a$ and the combination of $b$ and $c$ (where $b$ and $c$ are connected together).