Ratio of focal length to the diameter of the aperture of a camera lens is defined as its F number. For such a camera lens F number is given to be $\frac{25}{3}$ . If a point object is kept $50 \mathrm{cm}$ in front of this camera lens, it produces a real image with magnification of $0.2$ on film plate placed behind it. Now if the film plate is moved away from lens by $1 \mathrm{cm}$ for this location what is the width of blurred image on the screen ($\mathrm{in} \mathrm{mm}$). (Paraxial approximations are valid)