Who among the following is known as the 'Father of Taxonomy'?

Shreya read in her textbook that communicable diseases are caused by pathogens. These pathogens pass from patients to healthy persons causing the disease. She suggested her friends that we can prevent the spread of these diseases and even some of them can be eradicated.

$(a)$ What are the various methods of spread of communicable diseases?

$(b)$ What preventive measures can be taken to prevent the spread of communicable diseases?

$(c)$ Which values are displayed by Shreya in taking initiative ?

$(d)$ Suggest some school activity to promote such values in school students ?

$A$ $p-n$ photodiode is made of a material with a band gap of $2.0 \text{ eV}$. The minimum frequency of the radiation that can be absorbed by the material is nearly

$A$ square matrix $[a_{ij}]$ in which $a_{ij} = 0$ for $i \neq j$ and $a_{ij} = k$ (constant) for $i = j$ is called a

$A$ photon of energy $8\,eV$ is incident on a metal surface of threshold frequency $1.6 \times 10^{15}\,Hz$. The maximum kinetic energy of the emitted photoelectrons is ...............$eV$ $(h = 6.6 \times 10^{-34}\,Js)$.

$\frac{d}{d x} \sin ^{-1}\left(3 x-4 x^3\right)$ is equal to