Yes, it is dangerous to put your hand on an induction cooktop hob while it is on, especially if it's at a high power setting. Induction cooktops work by generating an electromagnetic field that induces heat directly into the cookware. When the cookware is placed on the hob, it becomes hot, and the heat can transfer to the surrounding surface.
If you put your hand on the hob while the cooktop is on, you risk burning or scalding your hand, as the surface can become extremely hot. The heat generated by the electromagnetic field can be intense, even if the cookware itself is not large or fully covering the hob. Additionally, induction cooktops cool down quickly after they are turned off, so touching the surface immediately after cooking may still be hazardous.
To avoid burns and injuries, it's crucial to exercise caution and never touch the hob while the induction cooktop is on or shortly after it has been in use. Always use potholders or oven mitts to handle hot cookware, and keep the cooking area clear of any items that could potentially come into contact with the cooktop surface while it is in use.