The whorl of bracts present below the inflorescence of $Helianthus$ $(sunflower)$ is

Bond dissociation energies of $HF$,$HCl$,and $HBr$ follow the order:

One mole of $N_2H_4$ loses $10$ moles of electrons to form a new compound $Z$. Assuming that all the nitrogen atoms appear in the new compound,what is the oxidation state of nitrogen in $Z$? (There is no change in the oxidation state of hydrogen.)

The ratio of the speed of the electrons in the ground state of hydrogen to the speed of light in vacuum is

Data Entry - Physics

If $a = \hat{i} + 4 \hat{j}$,$b = 2 \hat{i} - 2 \hat{j}$,and $c = 5 \hat{i} + 9 \hat{j}$,then $c$ is equal to: