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  Diagonal Relationship between Beryllium and Aluminium The ionic radius of Beryllium (Be 2+) is estimated to be nearly 31 pm; the charge/radius ratio Or e/m ratio is nearly the same as that of the Al 3+ ion. Hence beryllium resembles aluminium in these ways. Some of the similarities are given below: » Like Aluminium, Beryllium(be) is not readily attacked by acids H+ donor because of the formation of an oxide film on the surface of the metal by reacting with oxygen, i.e. they are rendered passive by nitric acid. » Beryllium hydroxide[[Be(OH)4]2] dissolves in excess of alkali to give a beryllate ion, [ Be(OH)4]2– just as aluminium hydroxide[Al(OH)3] gives aluminate ion, [Al(OH)4] » The chlorides of metals beryllium and aluminium have Cl– bridged chloride structure in vapour phase. Both the chlorides are soluble in organic solvents and are strong as Lewis acids They are used as Friedel Craft catalysts. » Beryllium(Be) and aluminium(Al) ions have strong tendency to form complexes, (Be...

A tower, x metre, has a flagstaff at its top. The tower and flagstaff subtends equal angles at a point distant y metre from the foot of the tower. Then find the length of the flagstaff ( in metre). 

 1. A point charge +q, is placed at a distance d from an isolated conducting plane. The field at a point P on the other side of the plane is  (a) directed perpendicular to the plane and away from the plane.  (b) directed perpendicular to the plane but towards the plane.   (c) directed radially away from the point charge.  (d) directed radially towards the point charge.  2. A positively charged particle is released from rest in an uniform electric field. The electric potential energy of the charge  (a) remains constant because the electric field is uniform.  (b) increases because the charge moves along the electric field.  (c) decreases because the charge moves along the electric field.  (d) decreases because the charge moves opposite to the electric field.  3. Which of the following characteristics of electrons determine the current in a conductor?   (a) Drift velocity alone   (b) Thermal velocity alone...

                    Banking of road The maximum permissible velocity with which vehicle can go round a level curved road without skidding depends on the coefficient of friction ( μ)  between the tyres and the road The value of  μ  decreases when road is smooth or tyres of the vehicle are worn out or the road is wet and so on. Thus force of friction is not a reliable source for providing the required centripetal force to the vehicle. A safer course of action would be to raise outer edge of the curved road shove the inner edge. By doing so, a component of normal reaction of the road shall be spared to provide the centripetal force. This phenomenon of raising outer edge of the curved road above the inner edge is called banking of roads . It's facilitates vehicles to turn without slipping. Three forces are acting on the vehicle as shown in Figure below.  (i) Weight mg of the vehicle acting vertically downwards.  (ii)...

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