C,Si and Ge have the same lattice structure. Why is C insulator while Si and Ge intrinsic semiconductor.

Write the different energy levels of Si and Ge crystals.

What is the C.G.S and S.I unit of speed?

Assume the thermal conductivity of copper is 4 times that of brass.Two rods of copper and brass having the same length and cross section are joined end to end.The free and end of copper is at 0°C and the free end of brass is at 100°C.Calculate the temperature of the junctionof thw two rods at equilibirum.

What is the C.G.S and S.I unit of velocity?

What it he C.G.S and S.I. unit of displacement?

What is the C.G.S and S.I. unit of acceleration?

What is intrinsic semiconductor? Draw the schematic two dimensional diagram of Si on Ge structure at low temperature.