It is theoretically possible for a substance to have a negative value of cubical expansivity, which means that the substance would contract rather than expand when the temperature increases. However, it is very rare for a substance to have a negative value of cubical expansivity over a significant range of temperatures.
One example of a substance that has a negative value of cubical expansivity over a limited range of temperatures is water. Water has a positive value of cubical expansivity at...
The answer is A
In the depletion layer, electrons combine with holes producing charge density so that region is depleted of charge carriers but it has charge density .
Conclusion: Neutral but still having non zero charge density .

