Rotation of the frame with a current in a magnetic field is used in measuring instruments. By the angle, you can determine the current in the frame. The measured current is directly proportional to the angle of deflection of the arrow: l = C / NSB * a, where C is a constant proportionality factor. When the current passes through the frame, it rotates through a certain angle and is held in this position due to the elastic force that occurs in the springs.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.