A small source of sound is in uniform circular motion of radius R and angular speed / 10 rad s ⁻¹ . It emits continuous sound of fixed frequency f₀ . A detector placed at a distance 2 R from the centre and in the plane of the circle records frequencies with maximum value 1200 Hz and minimum value 800 Hz . Take the speed of sound to be 330 ~m ~s ⁻¹ . Select the correct statement(s).