Question

The two interfering waves have intensities in the ratio 9 : 4. The ratio of intensities of maxima and minima in the interference pattern will be

• A. 1 : 25
• B. 25 : 1
• C. 9 : 4
• D. 4 : 9

Answer 1

The correct option is B 25 : 1

$\frac{l_{max}}{l_{min}}={\left(\frac{\sqrt{\frac{l_1}{l_2}+1}}{\frac{\sqrt{l_1}}{\sqrt{l_2}}-1}\right)}^2={\left(\frac{\sqrt{\frac{9}{4}+1}}{\sqrt{\frac{9}{4}}-1}\right)}^2=\frac{25}{1}$