Two plane mirrors \( M_1 \) and \( M_2 \) are at right angle to each other, shown. A point source ‘P’ is placed at \( a \) and \( 2a \) meter away from \( M_1 \) and \( M_2 \) respectively. The shortest distance between the images thus formed is: (Take \( \sqrt{5} = 2.3 \).)
