education infogram

The high. voltages used  to transmit electrical power around a country are dangerous. That is why the cables that carry the power are supported high above people, traffic and building on tall pylons. Sometimes the cables are buried underground, but this is much more expensive, and the cables must safely insulated. There is a good reason for using high voltages. It means that the current flowing in the cables is relatively low, and this wastes less energy. We can understand this as follows.                                                 When a current flows in a wire or cable, some of the energy it is carrying is lost because of the cable's resistance - the cables get war,. A small current wastes less energy than a high current. Electrical engineers do everything they can do to reduce the current to half its value ( by doubling the voltage), the losses will be one-quarter of their previous value. This is because the power losses in cables are proportional to the square of the curre

 Condensation polymerisation can also be used to make other polymers with properties different from those of nylons. Polyesters are condensation copolymers made from two monomers. One monomer has an alcohol group (---OH) at each end. When the monomers react, an ester link is formed, with water being lost each time.  One each polymers has the trade 'Terylene'. Like nylon, Terylene clothing is generally softer than that made from nylon. The ester linkage that joins the monomer units in the man-made fibre Terylene can be broken down by acid or alkaline hydrolysis. So it is not good news if spots of alkali fall on your shirts or sweaters!

                                                      The villa was small and square, standing in its tiny garden with an air of pink-faced determination. Its shutters had been faded by the sun to a delicate creamy green, cracked and bubbled in places. The gardens, surrounded by tall fuchsia hedges, had the flower-beds worked in complicated geometrical patterns, marked with smooth white stones. The white cobbled paths, scarcely as wide as a rake's head, wound laboriously round beds hardly of stars, half-moons, triangles, and circles, all overgrown with a shaggy tangle of flowers run wild. Roses dropped petals that seemed as big and smooth as saucers, flame-red, moon-white, glossy, and unwrinkled; marigolds like broods of shaggy suns stood watching their parent's progress though the sky. In the low growth the pansies pushed their velvety, innocent faces through the leaves, and the violets drooped sorrowfully under their heard-shaped leaves. The bougainvillaea that sprawled luxur