Consider a proton moving parallel to a positively charged infinite thin rod at rest, as shown below.

Proton $\vec{v}$
First consider the frame in which the rod is at rest (the frame assumed in the diagram).
-(e) The rod creates an electric field in that frame.

Question

Consider a proton moving parallel to a positively charged infinite thin rod at rest, as shown below.
  
Proton $\vec{v}$
First consider the frame in which the rod is at rest (the frame assumed in the diagram).
-(e) The rod creates an electric field in that frame.

Quizplus · Accepted Answer

In the frame where the rod is moving, it will appear to have an electric field due to the relativistic effect of length contraction, which affects the distribution of charges and thus creates an electric field.

Consider a Proton Moving Parallel to a Positively Charged Infinite v⃗\vec{v}v

Consider a Proton Moving Parallel to a Positively Charged Infinite $\vec{v}$