Inspite of long range order in the arrangement of particles why are the crystals usually not perfect?

Arrange the following substances in increasing order of forces of attraction between the particles— water, sugar, oxygen.

Why dust particles take long time to settle down ?

Read the following passage and answer the questions. Ultrafiltration is the process of separating the colloidal particles from the solvent and soluble solutes present in the colloidal solution by specially prepared filters, which are permeable to all substances except the colloidal particles. Colloidal particles can pass through ordinary filter paper because the pores are too large. However, the pores of filter paper can be reduced in size by impregnating with collodion solution to stop the flow of colloidal particles. The usual collodion is a 4% solution of nitrocellulose in a mixture of alcohol and ether. An ultra-filter paper may be prepared by soaking the filter paper in a collodion solution, hardening by formaldehyde and then finally drying it. Thus, by using ultra-filter paper, the colloidal particles are separated from rest of the materials. Ultrafiltration is a slow process. To speed up the process, pressure or suction is applied. The colloidal particles left on the ultra-filter paper are then stirred with fresh dispersion medium (solvent) to get a pure colloidal solution. Why ordinary filter paper can not be used for ultrafiltration ?

The extent of localisation of a particle is determined roughly by its de-Broglie wave.If an electron is loclalized within the nucleus (of size about 10^(-14)m) of an atom,what is its energy?Compare this energy with the typicla binding energyies(of the order of a few Me) in a nucleus and hyence argue why electrons cannot reside in a nucleus.

What is the meaning of the terms frequency of an altrnating current? What is its value in India? Why is an alternating current considered to be advntageous over direct current for long range transmission of electric energy?

Read the following passage and answer the questions. Adsorption is surface phenomenon and its differ from absorption, Which occurs throughout the body of the substance which abosorbs. In physisorption, the attractive forces are mainly van der waals forces while in chemisorption actual bonding occuars between the particles of absorbent and absorbate. Generelly, easily liquifying gases are absorved more easily on the surface of a solid as compared to the gases which are liquified with difficulty. Adsorption increases with the increase in pressure and decreases as the temparature is increased. Arrange the following gases in the decreasing order of the ease with which they are adsorbed on charcoal. H_2 , CH_4 , CO_2 and NH_3

Long , flattened and usually unbranched units arranged in parallel stacks in endoplasmic reticulum are called

Arrange following complex ions in increasing order of crystal field splitting energy (Delta_0) : [Cr(Cl_6]^(3-) , [Cr(CN)_6]^(3-) , [Cr(NH_3)_6]^(3+) .