The expected answers were:

1. Resistivity is the specific resistance of a unit length of a material with a unit cross-sectional area.

      

OR
            Resistivity
Where R is the resistance of the material
             A is the cross-sectional area of the material
               l is the length of the material
The S.I. unit of resistivity,

1.  The mathematical relationship that connects the two quantities is
   OR
   Resistivity is the reciprocal of conductivity

1. Length of the cable = 50m

Resistance of the cable=0.067

       
A  = 2.84 x 10-8 x 50 =142 x 10-6 = 2.1194 x 10-5 m2
           0.067              0.067
            A = 21.19 mm2

1. Conductivity,  

                             =            1     
                                     2.84 x 10-8
                                              =  3.521 x 107( m)-1
                                              =  0.352 x 108( m)-1

The question was on Direct Current Circuit Theory. It was quite popular with the candidates. However, the performance was disappointing.

Most of the candidates could not define resistivity. They also could not differentiate between resistivity and resistance which showed that they did not do well in part (a) and (c), but more candidates stated correctly in part (b)the relationship between resistivity and conductivity.