An electron enters with a velocity `vecv=v_0hati` into a cubical region (faces parallel to coordinate planes) in which there are uniform electric and magnetic fields. The orbit of the electron is found to spiral down inside the cube in plane parallel to the x-y plane. Suggest a configuration of fields `vecE` and `vecB` that can lead to it.

Explanation

To solve the problem, we need to determine the configuration of the electric field \(\vec{E}\) and the magnetic field \(\vec{B}\) that allows an electron to spiral down in a plane parallel to the x-y plane when it enters with an initial velocity along the x-axis.

### Step-by-Step Solution:

1. **Identify the Initial Conditions:**
- The electron enters with a velocity \(\vec{v} = v_0 \hat{i}\), meaning it is moving along the positive x-direction.
- The electron is negatively charged, with charge \(q = -e\).

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