Prabin Kalikote

The table with 7 periods and 18 groups that are designed in such a waythat it can arrange all elementsaccording to their properties, similarities die dissimilarities,etc which helps in the study of elements is called aperiodic table.

The contribution of fohn Dalton in the classification ofelements is that he profounded the atomic theory andsaid that the atoms of different elements havedifferent atomic weights.

The contribution of Prout is that he said the atomic weight of an element is a simple multiple of the atomic weight of hydrogen.

The process of grouping the elements on the basis ofthe similarities and differences for theeasyrecognition and study of the element and theirproperties and characteristics is called the classification ofelements.

The transformer is a device that increases or decreases the voltage of the alternating current. As the voltage of current produced in powerhouse is generally low, without the use of a transformer it cannot be made high to transmit current through long distances.

The core of a transformer should be laminated to minimize energy loss due to the production of aneddy current.

We know, tungsten wire has low resistance and it cannotconvert electricalenergyto heatenergyand also oxidizeat high temperature. So, it is not used in the heater.

We know, nichrome is an alloy of nickel and chromiummetals. It has high resistance and doesn't oxidize atvery high temperatures. So,nichromewire is used in anelectric heater but not a copper wire.