Identify from the following plant parts,the major contributors to human food?

$A$ wire of length $l$ is bent into a circular loop of radius $R$ and carries a current $I$. The magnetic field at the centre of the loop is $B$. The same wire is now bent into a double loop of equal radii. If both loops carry the same current $I$ and it is in the same direction,the magnetic field at the centre of the double loop will be

If $\alpha = \frac{5}{2! 3} + \frac{5 \cdot 7}{3! 3^2} + \frac{5 \cdot 7 \cdot 9}{4! 3^3} + \ldots$,then $\alpha^2 + 4\alpha$ is equal to

If the sum of the distances of a point $P$ from two perpendicular lines in a plane is $1$,then the locus of $P$ is a

The difference between volume and pressure coefficients of an ideal gas is

In which of the following reactions does $H_2O_2$ act as a reducing agent?