Two initially identical samples A & B of pure germanium are doped with donors to concentrations of 1 × 1020 and 3 × 1020 respectively. If the hole concentration in A is 9 × 1012 then the hole concentration in B at the same temperature will be
1
3 × 1012 m-3
2
7 × 1012 m-3
3
11 × 1012 m-3
4
27 × 1012 m-3