The total work done on a particle is equal to the change in its kinetic energy. This is applicable:

Pure $Si$ at $500\, K$ has equal number of electron $(n_e)$ and hole $(n_h)$ concentrations of $1.5 \times 10^{16} \,m^{-3}$. Doping by indium increases $n_h$ to $4.5 \times 10^{22} \,m^{-3}$. The doped semiconductor is of

Assertion : Free electrons always keep on moving in a conductor even then no magnetic force acts on them in a magnetic field unless a current is passed through it.
Reason : The average velocity of free electrons is zero.

In a diffraction experiment from a single slit,the angular width of the central maxima does $NOT$ depend upon

Identify the blank spaces $A, B, C$ and $D$ given in the following table and select the correct answer.

Types of Microbes	Scientific Name	Commercial Product
Bacterium	$A$	Clot buster enzyme
$B$	Aspergillus niger	Citric acid
Fungus	Trichoderma polysporum	$C$
Bacterium	$D$	Butyric acid

$A$ disc has mass $m$ and radius $R$. How much tangential force should be applied to the rim of the disc so as to rotate it with angular velocity $\omega$ in time $t$?