<prompt> Regarding variable orifice flowmeters true isThe tube must be slightly inclined to the vertical to avoid frictionThe bobbin is scored to avoid frictionAre accurate only for laminar flowAn orifice has diameter shorter than its length  <response>: The variable orifice flowmeter is rotameter. The tube is vertically mounted. the bobbin is scored so that it rotates without sticking. Tube is gas specific and laminar flow occurs at the base and turbulent flow occurs at the top. 