In a compound,$C, H,$ and $N$ atoms are present in the ratio $9 : 1 : 3.5$ by weight. If the molecular weight of the compound is $108$,what is its molecular formula?

Which of the following substances,if introduced into the blood stream,causes coagulation of blood at the site of its introduction?

Describe Mendelian disorders.

If $a \cdot \hat{i} = a \cdot (\hat{i} + \hat{j}) = a \cdot (\hat{i} + \hat{j} + \hat{k})$, then $a$ is equal to

A prism of angle $75^\circ$ and refractive index $\sqrt{3}$ is coated with thin film of refractive index $1.5$ only at the back exit surface. To have total internal reflection at the back exit surface the incident angle must be . . . . . . .
$(\sin 15^\circ = 0.25$ and $\sin 25^\circ = 0.43)$

If Avogadro number $N_A$ is changed from $6.022 \times 10^{23} \text{ mol}^{-1}$ to $6.022 \times 10^{20} \text{ mol}^{-1}$,this would change: