Solid state

Question 1

what are smart materials?

Answer 1

Materials that have one or more properties that can be change in a controlled fashion by external stimuli, such as stress, temperature, moisture, pH, electric and magnetic fields.

Question 2

What are Piezoelectric Materials

Answer 2

Piezoelectric Materials are materials that have the ability to generate
internal electrical charge from applied mechanical stress.
Examples- Tourmaline
• Quartz
• Topaz
• Rochelle salt

Question 3

What are Electrochromic Material

Answer 3

Electrochromic Material: A material that changes its optical
properties (e.g. color) when a voltage is applied across it. They are
used in LCDs and Smart windows.
Examples-
• Tungsten oxide (WO3)
• Viologen mixed with TiO2

Question 4

What are Photochromic Materials? What are compounds used?

Answer 4

Photochromism is the reversible transformation of color upon exposure to light. This phenomenon is used in sunglasses.

• Azobenzen
• Diarylethene
• Spiropyran
• Silver Chloride

Question 5

What are Thermoresponsive Materials?

Answer 5

Thermoresponsive materials have the ability to respond to a change in temperature

Question 6

What are Quantum tunneling composite materials?

Answer 6

Quantum Tunneling Composites are composite martials of metal and non-conducting elastomeric binders, used as pressure sensors.

Question 7

What are Mechanochromic/Mechanoluminescence Materials?

Answer 7

Mechanochromism refers to intensity and/or color changes of (solid-state) materials induced by mechanical forces, such as rubbing, crushing, pressing, shearing, or smearing.

Mechano-sensitive materials especially those with fluorescent responses, named as mechanochromic Luminiscence or mechano-luminiscence materials.

Question 8

Examples of crystalline solids?

Answer 8

Diamond
NaCl
Solid Iodine
Gold Quartz

Question 9

Examples of amorphous solids?

Answer 9

Glass
Plastic
Rubber

Question 10

Why do crystalline solids have a sharp melting poin?

Answer 10

Because all the particles in the portion are same

Question 11

Why do amorphous solids melt at different temperatures?

Answer 11

Because every portion of amorphous solid is different from the neighboring portion.

Question 12

Due to the difference of arrangement of particles in different direction, which physical properties do we observe?

Answer 12

Electrical Resistance
Refractive Index
Thermal Expansion

Question 13

What does isotropic mean?

Answer 13

Various physical properties are same in all direction

Question 14

Which material is isotropic?

Answer 14

Amorphous solids

Question 15

What is crystallinity?

Answer 15

Repeating or periodic array over large atomic distances.

3-D pattern in which each atom is bonded to its neighbouring atom

Question 16

What is a crystal structure?

Answer 16

Spatial arrangement of atoms, ions or molecules.

Question 17

How is a crystal structure described?

Answer 17

basis + lattice = crystal structure

Question 18

Define a lattice

Answer 18

A lattice is a regular infinite arrangement of points in which every point has
the same environment as any other point. A lattice in 2 dimensions is called
a net and a regular stacking of nets gives us a 3-dimensional lattice.

Question 19

Differentiate between primitive and non primitive unit cell

Answer 19

Primitive unit cell
-The unit cell in this case is larger.
-It exhibits the rectangular symmetry.
-The basis consists of the two atoms: one atom is located in the corner of
the unit cell and another atom in the center of the unit cell.

Non-primitive unit cell

• Parallelogram
• We have just one atom in a unit cell.