Electric field [img=14x24]1803a374c4e0b52.png[/img] and magnetic field [img=14x24]1803a374ccd1dcd.png[/img] are perpendicular to the particle’s velocity and to each other as shown in the figure. What is the speed that the particles must have when they leave the source for them to be able to pass through the very narrow and long field region? . (In form of / , if fraction)
举一反三
- Is there a relationship between the electric field [img=14x24]1803a376c9db0a5.png[/img] and magnetic field [img=14x24]1803a376d21ab6b.png[/img] of an electromagnetic wave at each point in vacuum? A: No any relationship. B: Yes, [img=14x24]1803a376db08c62.png[/img] is perpendicular to [img=14x24]1803a376e3d9bc3.png[/img] and [img=59x19]1803a376eca6699.png[/img]. C: Yes, [img=14x24]1803a376db08c62.png[/img] is parallel to [img=14x24]1803a376e3d9bc3.png[/img] and [img=59x19]1803a376eca6699.png[/img]. D: No relationship in direction but [img=59x19]1803a376eca6699.png[/img] in magnitude.
- What is the net force on a magnetic dipole in a uniform magnetic field [img=14x24]1803a3749667c37.png[/img]? A: Nonzero and in the direction of [img=14x24]1803a3749f40258.png[/img]. B: Nonzero and in the direction of [img=28x26]1803a374a7784ea.png[/img]. C: Nonzero and perpendicular to [img=14x24]1803a3749f40258.png[/img].[img=14x24]1803a3749f40258.png[/img] D: zero.
- 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
- If there is no charge inside the Gaussian surface, the field [img=14x24]180356c02c2f797.png[/img] on the surface must be zero everywhere.
- There exists an induced current flowing clockwise in the conducting loop shown in Figure. What is the direction of the magnetic field through the loop and how does the field vary in magnitude?[img=111x83]1803a3760763dd5.png[/img] A: Into the page and increasing. B: Into the page and decreasing. C: Into the page and steady. D: Out of the page and decreasing.