The magnetic field is not harmful, but it may cause some medical devices to __________________.
举一反三
- The curl equation [img=154x44]1803a2a153c85f5.png[/img]shows that : A: The time-varying magnetic field can generate an electric field, in which the elecric field lines is closed around the magnetic field line. B: The time-varying magnetic field can generate a magneitc field, in which the magnetic field lines is closed around the electric field line. C: The magnetic field lines is closed themselves. D: Flux continuity
- There is no magnetic field in an ideal conductor, but there is a magnetic field inside because of the surface current。
- The<br/>magnetic field lines are used to visually describe the distribution<br/>of the magnetic field around the magnet. For the following<br/>statement,( <br/>) is wrong. A: Each<br/>magnetic field line is a closed loop curve B: No<br/>two magnetic field lines can cross each other C: The<br/>length of the magnetic field line reflects the strength of the<br/>magnetic field D: The<br/>tangential direction of any point on any of the magnetic lines is the<br/>direction of the magnetic field at that point
- Contact lenses belong to Class-III medical devices of medical devices in medicine.
- A circular loop of wire is held in a uniform magnetic field, with the plane of the loop perpendicular to the field lines. Which of the following will not cause a current to be induced in the loop? A: crushing the loop B: rotating the loop about an axis perpendicular to the field lines C: keeping the orientation of the loop fixed and moving it along the field lines D: pulling the loop out of the field