The type of field generated by a DC tacho-generator is A: pulsating magnetic field B: static field C: rotating field D: do not need field
The type of field generated by a DC tacho-generator is A: pulsating magnetic field B: static field C: rotating field D: do not need field
What can be said about the field A: The field is left unplanted. B: The field is lying waste. C: The field is left open to playing. D: The field is played with this year,
What can be said about the field A: The field is left unplanted. B: The field is lying waste. C: The field is left open to playing. D: The field is played with this year,
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 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 difference in depth of field produced by between 85mm lens of the medium camera and of 135 camera is ______. A: no difference B: The depth of field by 135 camera is shallower. C: The depth of field by the medium camera is shallower. D: The depth of field by 135 camera is deeper.
The difference in depth of field produced by between 85mm lens of the medium camera and of 135 camera is ______. A: no difference B: The depth of field by 135 camera is shallower. C: The depth of field by the medium camera is shallower. D: The depth of field by 135 camera is deeper.
The Biot-Savart Law is used to( ) A: determine the magnetic field created by an electric current B: determine the electric field created by an electric current C: determine the force field created by an electric current D: determine the magnetic field created by individual point charges E: determine the electric field created by individual point charges
The Biot-Savart Law is used to( ) A: determine the magnetic field created by an electric current B: determine the electric field created by an electric current C: determine the force field created by an electric current D: determine the magnetic field created by individual point charges E: determine the electric field created by individual point charges
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
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
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
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
In the vector field, the vector line is such a curve where ( ) A: The tangent direction at each point on it is orthogonal to the direction of the vector field at that point. B: The tangent direction at each point on it is parallel to the direction of the vector field at that point. C: The value of each point on it is equal to the value of the vector field at that point. D: The vector line is the geometric curve of the vector field function.
In the vector field, the vector line is such a curve where ( ) A: The tangent direction at each point on it is orthogonal to the direction of the vector field at that point. B: The tangent direction at each point on it is parallel to the direction of the vector field at that point. C: The value of each point on it is equal to the value of the vector field at that point. D: The vector line is the geometric curve of the vector field function.
场论可以分为classic field theory和quantum field theory
场论可以分为classic field theory和quantum field theory
There is no magnetic field in an ideal conductor, but there is a magnetic field inside because of the surface current。
There is no magnetic field in an ideal conductor, but there is a magnetic field inside because of the surface current。