Advertisements
Advertisements
प्रश्न
The relation a ≠ b ≠ c and α ≠ β ≠ γ represents which crystal system?
(A) Orthorhombic
(B) Tetragonal
(C) Triclinic
(D) Monoclinic
Advertisements
उत्तर
(C) Triclinic
APPEARS IN
संबंधित प्रश्न
Why are solids rigid?
Why do solids have a definite volume?
Classify the following as amorphous or crystalline solids:
Polyurethane, naphthalene, benzoic acid, teflon, potassium nitrate, cellophane, polyvinyl chloride, fibre glass, copper.
Why is glass considered a super cooled liquid?
Refractive index of a solid is observed to have the same value along all directions. Comment on the nature of this solid. Would it show cleavage property?
Define the term ‘amorphous’.
What makes a glass different from a solid such as quartz? Under what conditions could quartz be converted into glass?
‘Stability of a crystal is reflected in the magnitude of its melting points.’ Comment. Collect melting points of solid water, ethyl alcohol, diethyl ether and methane from a data book. What can you say about the intermolecular forces between these molecules?
Write any two differences between amorphous solids and crystalline solids
Why does sodium chloride on heating with sodium vapours acquire yellow colour?
Which among the following is not an example of amorphous solids?
Most crystals show good cleavage because their atoms, ions or molecules are ____________.
“Crystalline solids are anisotropic in nature″. What is the meaning of anisotropic in the given statement?
A crystalline solid ____________.
Which of the following is an amorphous solid?
Why some glass objects from ancient civilisations are found to become milky in appearance?
Which of the following amorphous solid is used as photovoltaic material for conversion of sunlight into electricity?
Amorphous solids are ______.
Amorphous solid can also be called:
(i) pseudo solids
(ii) true solids
(iii) supercooled liquids
(iv) supercooled solids
Which of the following features are not shown by quartz glass?
(i) This is a crystalline solid.
(ii) Refractive index is same in all the directions.
(iii) This has definite heat of fusion.
(iv) This is also called super cooled liquid.
Under which situations can an amorphous substance change to crystalline form?
Assertion A: Sharp glass edge becomes smooth on heating it upto its melting point.
Reason R: The viscosity of glass decreases on melting.
Choose the most appropriate answer from the options given below.
An ionic solid AB2 isomorphous to the rutile structure (a tetragonal system with the effective number of formula units = 2) has edge lengths of the unit cell of 4Å, 4Å and 7Å. The density of the substance is ______ mg/cc. (if its formula weight is 80. The NA = 6 × 1023 and express your answer in mg/cc using four significant digits.)
