| List I | List II | ||
| A | Nitrogen oxides in air | I | Eutrophication |
| B | Nitrogen oxides in air | II | Eutrophication |
| C | Carbon dioxide | III | Global warming |
| D | Phosphate fertilisers in water | IV | Acid rain |
Choose the correct answer from the options given below:
Calculate the potential for half-cell containing 0.01 M K\(_2\)Cr\(_2\)O\(_7\)(aq), 0.01 M Cr\(^{3+}\)(aq), and 1.0 x 10\(^{-4}\) M H\(^+\)(aq).

A square loop of sides \( a = 1 \, {m} \) is held normally in front of a point charge \( q = 1 \, {C} \). The flux of the electric field through the shaded region is \( \frac{5}{p} \times \frac{1}{\varepsilon_0} \, {Nm}^2/{C} \), where the value of \( p \) is: