Question

The light beams of intensities in the ratio of $9:1$ are allowed to interfere. What will be the ratio of the intensities of maxima and minima ?

• A. 3 : 1
• B. 4 : 1
• C. 25 : 9
• D. 81 : 1

Answer 1

Answer: (B)

The light beams with intensities being in the ratio $\frac{9}{1}$, so the amplitudes are in the ratio $\frac{3}{1}$.
So, the maximum and minimum intensities are in the ratio $\frac{(3+1{)}^2}{(3-1{)}^2}=\frac{4^2}{2^2}=\frac{16}{4}=\frac{4}{1}$.