The correct choice among the given regarding formula of Conductivity κ is -

a.  1RlA

b.  G*R

c.  Λm

d.  lA


1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

As we know that, conductance is reciprocal of resistance and conductivity is the conductance of 1 cm3 of substance. Also, conductivity is reciprocal of resistivity.
 
κ=1ρR=ρlAρ=Γ·Al=k=1R·Alk=1R,lA=1R×G*=G*R
 
Hence, options (a) and (b) are the correct choices.