Question

If the ratio of amplitudes of two sound waves is \(4:3\), then the ratio of maximum and minimum intensities is

• A. \(1:7\)
• B. \(1:49\)
• C. \(49:1\)
• D. \(7:1\)

Hint:

In interference, use \[ I_{\max} \propto (A_1 + A_2)^2,\quad I_{\min} \propto (A_1 - A_2)^2 \]

Answer 1

The Correct Option is C

Step 1: Relation between intensity and amplitude.
\[ I \propto A^2 \]
Step 2: Maximum and minimum amplitudes.
\[ A_{\max} = 4 + 3 = 7, \quad A_{\min} = 4 - 3 = 1 \]
Step 3: Ratio of intensities.
\[ I_{\max} : I_{\min} = 7^2 : 1^2 = 49 : 1 \]
Step 4: Conclusion.
The required ratio is 49:1.