The interference pattern is obtained with two coherent light sources of intensity ratio n. In the interference pattern, the ratio $\frac{{I}_{max}-{I}_{min}}{{I}_{max}+{I}_{min}}$ will be

1.$\frac{\sqrt{n}}{n+1}$

2. $\frac{2\sqrt{n}}{n+1}$

3. $\frac{\sqrt{n}}{{\left(n+1\right)}^{2}}$

4.$\frac{2\sqrt{n}}{{\left(n+1\right)}^{2}}$