ASOC Exam Syllabus and Sample Question /ANswers

The circuit shown here is a simple circuit with one load or resistor across a voltage source (e.g. a battery).

E=IR=I(1/S) or E=I/S

R=1/S or S=1/R

Materials which allow the flow of electric current through them are called conductors. Metals are known to be good conductors, with copper and silver among the best. The conductivity of a particular material depends on the number of free electrons present in it. A conductor may be a very good conductor, a fairly good conductor or a poor conductor. So, a greater conductivity or conductance implies lesser resistance and a lesser conductivity implies greater resistance. So, conductance (conductance is expressed in siemens, S) and resistance (R) are the same thing but from opposite viewpoints. They are said to be reciprocal of each other, i.e.