Give examples of intrinsic semiconductors.

Which from the following dopants is used in germanium to produce $p-$type semiconductor?

Identify the incorrect set from the following:

Classify the following materials into superconductors,conductors,semiconductors,and insulators: $Cu$,$Al$,$Si$,$Ge$,glass,Teflon,$Au$,$Pt$,$CuO$ (at low temperature),graphite,carbon black,and alloys at low temperature.

Which of the following compounds is metallic and ferromagnetic?

When mechanical stress is applied to a crystal,a small amount of electricity is produced. This property is called ........