$A$ $Ge$ specimen is doped with $Al$. The concentration of acceptor atoms is $\sim 10^{21} \, \text{atoms}/m^3$. Given that the intrinsic concentration of electron-hole pairs is $\sim 10^{19}/m^3$, the concentration of electrons in the specimen is:

The compound $CH_3-C(CH_3)=CH-CH_3$ on reaction with $NaIO_4$ in the presence of $KMnO_4$ gives :-

$A$ charged particle moves through a magnetic field perpendicular to its direction. Then

Let the vectors $\overline{a}, \overline{b}, \overline{c}$ be such that $|\overline{a}|=2, |\overline{b}|=4$ and $|\overline{c}|=4$. If the projection of $\overline{b}$ on $\overline{a}$ is equal to the projection of $\overline{c}$ on $\overline{a}$ and $\overline{b}$ is perpendicular to $\overline{c}$,then the value of $|\overline{a}+\overline{b}-\overline{c}|$ is

Fraunhofer lines are produced by the absorption of light in

In eubacteria,a cellular component that resembles eukaryotic cell is