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EEJ MAIN Physics QUESTION #7025
Question 1
Two coherent waves interfere, resulting in a ratio of maximum to minimum intensity of $16$. Determine the ratio of the individual wave intensities.
  • $16 : 9$
  • $25 : 9$✔️
  • $4 : 1$
  • $5 : 3$
Correct Answer Explanation

$\frac{I_{max}}{I_{min}} = \left( \frac{a_1 + a_2}{a_1 - a_2} \right)^2 = 16 \implies \frac{a_1 + a_2}{a_1 - a_2} = 4$.

$a_1 + a_2 = 4a_1 - 4a_2 \implies 5a_2 = 3a_1 \implies \frac{a_1}{a_2} = \frac{5}{3}$.

Intensity ratio $\frac{I_1}{I_2} = \left( \frac{a_1}{a_2} \right)^2 = \frac{25}{9}$.