Select the correct statements.
(A) Crystalline solids have long range order.
(B) Crystalline solids are isotropic.
(C) Amorphous solids are sometimes called pseudo solids
(D) Amorphous solids soften over a range of temperatures.
(E) Amorphous solids have a definite heat of fusion
Choose the most appropriate answer from the options given below:
(A) Crystalline solids have long range order.
(B) Crystalline solids are isotropic.
(C) Amorphous solids are sometimes called pseudo solids
(D) Amorphous solids soften over a range of temperatures.
(E) Amorphous solids have a definite heat of fusion
Choose the most appropriate answer from the options given below:
- (A)(B), (D) only
- (B)(A), (B), (E) only
- (C)(A), (C), (D) only✓ Correct
- (D)(C), (D) only
Answer: (C)
Solution
Crystalline solids are built on a lattice that repeats in all directions, so they possess long range order, and because the arrangement of particles differs along different directions their physical properties are direction dependent, which makes them anisotropic rather than isotropic. Amorphous solids have order only over short distances; their particles are frozen in a disordered arrangement like that of a very viscous liquid, so they are described as pseudo solids and they soften gradually over a range of temperatures instead of melting sharply. With no sharp melting point they also have no definite heat of fusion. The correct statements are that crystalline solids have long range order, that amorphous solids are sometimes called pseudo solids, and that amorphous solids soften over a range of temperatures.
JEE Main · 2021 · 27 Jul 2021 · Shift 2 · Single correct option