Crystalline solids possess $......$.

Which one of the following is used as a piezoelectric material?

Which of the following is an example of a covalent crystal solid?

Explain paramagnetism and diamagnetism. Write a note on ferromagnetism. Explain antiferromagnetism.

What is the effect of adding gypsum to cement?

For amorphous solids,select the correct option using $T$ (True) or $F$ (False) for the following statements:
$(1)$ They soften over a range of temperature.
$(2)$ Their physical properties like electrical conductivity and thermal conductivity are the same in all directions.
$(3)$ The arrangement of their particles is disordered.
$(4)$ They are hard and are less affected by pressure.