The lnductrack Ⅱ design can produce a very strong magnetic field even when the train runs more slowly by ______.
举一反三
- When the external magnetic field is removed, most or all of the magnetism of soft magnetic materials will not be lost, and the coercivity is very large.
- 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
- 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
- When the field surface is covered by gravel, soil erosion caused by rain and strong winds can be effectively prevented.（ ）
- Who______, Jim or Tom A: runs more slowly B: did more badly C: looks friendlier