What is your exact location if you are crossing the prime meridan and the altitude of polaris is 50?

If you are crossing the prime meridian, your longitude is 0 degrees. At an altitude of Polaris (the North Star) of 50 degrees, you would be located at a latitude of approximately 50 degrees North. This position places you in a part of the Northern Hemisphere, likely somewhere in Europe, northern Asia, or parts of Canada.