Public domain photos

The image shows a black and white drawing of a square with a compass on it, which is a drawing of an object with numbers and text written on it. The object appears to be a magnetic field, with the compass indicating the direction of the magnetic field.

The image shows a black and white drawing of a square with a compass on it, which is a drawing of an object with numbers and text written on it. The object appears to be a magnetic field, with the compass indicating the direction of the magnetic field.Open in library