Is it normal to use only one hand on the yoke while landing?
It is absolutely normal, in fact it's rare for a pilot to have more than one hand on the yoke at any one time as it isn't required. Movies will often show pilots manhandling yokes with two hands, but that's just Hollywood. The only time two hands is required is when extra strength is needed on the controls, for instance a hydraulic failure.
When landing a pilot will have one hand on the yoke (or stick) and one hand on the throttle, as throttle adjustments are needed to maintain the correct glide angle and initiate a go-around if required.