The ratio of the intensities of two interfering waves is 4 : 1. The ratio of maximum to minimum intensity is

Dear Student

Given
I₁/I₂ = (a₁/a₂)² = 4/1
a₁/a₂ = 2/1
We Know that
I_max/ I_min= (a₁ + a₂)²/ (a₁ - a₂)²
= (2 + 1)²/ (2 – 1)²
= 9 / 1
So,I_max: I_min= 9:1

I hope this answer will help you.
Thanks & Regards
Yash Chourasiya