Two polaroids \(\text{P}_1\) and \( \text{P}_ 2\) are placed with their axis perpendicular to each other. Unpolarised light \(\text{I}_0\) is incident on \(\text{P}_1\) . A third polaroid \(\text{P}_3\) is kept in between \(\text{P}_1\) and \(\text{P}_2\) such that its axis makes an angle 45° with that of \(\text{P}_1\). The intensity of transmitted light through \(\text{P}_2\) is