(i) This is a crystalline solid.
(ii) Refractive index is the same in all the directions.
(iii) This has a definite heat of fusion.
(iv) This is also called supercooled liquid.
Correct Answers:
(i) This is a crystalline solid.
(iii) This has a definite heat of fusion.
Explanation: Quartz glass is an amorphous solid and they do not have a definite heat of fusion.