Which one of the following is used in the baking of bread?

Which chemical must be applied to the roots to keep the leaves of a plant green?

How many numbers greater than $24000$ can be formed by using digits $1, 2, 3, 4, 5$ when no digit is repeated?

The bob of a simple pendulum is displaced from its equilibrium position $O$ to a position $Q$ which is at height $h$ above $O$ and the bob is then released. Assuming the mass of the bob to be $m$ and time period of oscillations to be $2.0\ s$,the tension in the string when the bob passes through $O$ is

$A$ rectangular loop of length $l$ and breadth $b$ is placed at a distance of $x$ from an infinitely long wire carrying current $i$ such that the direction of the current is parallel to the breadth. If the loop moves away from the current-carrying wire in a direction perpendicular to it with a velocity $v$,the magnitude of the induced emf in the loop is: ($\mu_0=$ permeability of free space)

Two identical short bar magnets,each having magnetic moment $M$,are placed a distance of $2d$ apart with their axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them is: