WAEC Physics 2015 Theory — Question 19

Model answer

(i) The coulomb (C) is the S.I. unit of electric charge - the quantity of electric charge that passes through a given section of a circuit when a steady current of one ampere flows for one second. (ii) Resistance is the property of a material that opposes the flow of (free) electrons/current through it; it determines the size of current that can pass through the material for a given voltage. Its S.I. unit is the ohm (Ω).