Which of the following is the correct electronic configuration of $Cr$ $(Z = 24)$?

Two identical square rods of metal are welded end to end as shown in figure $(a)$. $20 \text{ calories}$ of heat flows through them in $4 \text{ minutes}$. If the rods are welded as shown in figure $(b)$,the same amount of heat will flow through the rods in ...... $\text{min}$.

The total number of possible isomers of the compound $[Cu(NH_3)_4][PtCl_4]$ are:

$\int_{0}^{1000} e^{x - [x]} \, dx$ is equal to:

How many corners of $SiO_4$ units are shared in the formation of three-dimensional silicates?

Identify the blank spaces $a, b, c$ and $d$ given in the following table and select the correct answer.

Type of microbes	Scientific name	Commercial product
Bacterium	$a$	Clot buster
$b$	Aspergillus niger	Citric acid
Fungus	Trichoderma polysporum	$c$
Bacterium	$d$	Butyric acid