$DDT$ residues are rapidly passed through the food chain causing biomagnification because $DDT$ is:

The refracting angle of a prism is $A$ and the refractive index of the material of the prism is $\cot \frac{A}{2}$. The angle of minimum deviation is

Observe the following reaction: $2A + B \longrightarrow C$. The rate of formation of $C$ is $2.2 \times 10^{-3} \ mol \ L^{-1} \ min^{-1}$. What is the value of $-\frac{d[A]}{dt}$ (in $mol \ L^{-1} \ min^{-1}$)?

Which of the following oxides is amphoteric?

The energy spectrum of $\beta$-particles [number $N(E)$ as a function of $\beta$-energy $E$] emitted from a radioactive source is:

$\sec h^{-1}\left(\frac{1}{2}\right)-\operatorname{cosec} h^{-1}\left(\frac{3}{4}\right)$ is equal to