Question

Sounds from two identical sources $S_1$ and $S_2$ reach a point P directly in the same phase with net intensity $I_0$. The power of $S_1$ is now reduced to 64% of its initial value, and the phase difference between $S_1$ and $S_2$ is varied continuously. The maximum and minimum intensities now recorded at P are $I_{max}$ and $I_{min}$ respectively. Then

• A. I_max= 0.36 I₀, I_min= 0.09 I_o
• B. I_max= 0.64 I₀, I_min= 0.04 I_o
• C. I_max= 0.81 I₀, I_min= 0.01 I_o
• D. I_max= 1.64 I₀, I_min= 0.36 I_o

Answer 1

The correct option is B

I_max= 0.64 I₀, I_min= 0.04 I_o

$I_{max}=(1+0.8{)}^2\frac{I_0}{4}=0.81I_0;I_{min}=(1-0.8{)}^2\frac{I_0}{4}=0.01I_0$