Question

Light from two source, each of same frequency and travelling in same direction, but with intensity in the ratio 4 :1 interfere. Find ratio of maximum to minimum intensity.

• A. 1:1
• B. 4:1
• C. 16:1
• D. 9:1

Answer 1

The correct option is D

9:1

$\frac{I_{max}}{I_{min}}={\left(\frac{\sqrt{I_1}+\sqrt{I_2}}{\sqrt{I_1}-\sqrt{I_2}}\right)}^2={\left(\frac{\sqrt{\frac{I_1}{I_2}}+1}{\sqrt{\frac{I_1}{I_2}-1}}\right)}^2={\left(\frac{2+1}{2-1}\right)}^2=9:1$.