The monochromatic beam of light is incident at 60^o on one face of an equilateral prism of refractive index n and emerges from the opposite face making an angle $\mathrm{\theta }\left(\mathrm{n}\right)$ with the normal (see the figure). For $\mathrm{n}=\sqrt{3}$ the value of $\mathrm{\theta }$ is 60^o and $\frac{\mathrm{d\theta }}{\mathrm{dn}}=\mathrm{m}$. The value of $\mathrm{m}$ is