In which of the following is an ionic bond present?

Why is the motion of an electron in a solid different from that in an isolated atom?

If $V_0$ is the volume of a standard unit cell of germanium crystal containing $N_0$ atoms, then the expression for the mass $m$ of a volume $V$ in terms of $V_0, N_0, M$ and $N_A$ is [here, $M$ is the molar mass of germanium and $N_A$ is the Avogadro's constant].

The resistivity of a semiconductor depends on $........$.

If the lattice constant of this semiconductor is decreased,then which of the following is correct?

If $Cu$ (Copper) and $Ge$ (Germanium) are cooled to $70 \ K$,then: