<prompt> The intensity of colour in Doppler is determined by-Direction flowVelocity of flowStrength of returning echoNone of the above  <response>: The intensity of colour in Doppler is determined by magnitude of the Doppler shift The magnitude of the Doppler shift is propoionate to the blood flow velocity and the Doppler angle Ref : Introduction to Vascular Ultrasonography 6th Edition Pg : 63 