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An electron is ejected from the surface of a long, thick straight conductor carrying a current, initially in a dircction perpendicular to the conductor. The electron will a. ultimately return to the conductor b. move in a circular path around the conductor c. gradually move away from the conductor along a spiral d. move in a helical path, with the conductor as the axis

Short Answer

Expert verified
d. The electron will move in a helical path, with the conductor as the axis.

Step by step solution

01

Understand the Situation

An electron is ejected perpendicularly from a long, straight conductor carrying current. The magnetic field around a conductor can affect a charged particle like an electron.
02

Apply the Right-Hand Rule

The direction of the magnetic field around the conductor can be found using the right-hand rule: Point your thumb in the direction of the current, and your fingers will curl in the direction of the magnetic field. This means that the magnetic field around the conductor forms concentric circles.
03

Consider the Lorentz Force

The Lorentz force experienced by the electron, which is negatively charged, is given by \( \mathbf{F} = q(\mathbf{v} \times \mathbf{B}) \). The force will be perpendicular to both the velocity of the electron and the magnetic field lines.
04

Analyze Electron's Path

Due to the continuous perpendicular force from the magnetic field, the electron will move in a path that is perpendicular to both its initial velocity and the magnetic field lines. This results in a spiral or helical trajectory around the conductor.
05

Determine the Axis of Movement

Given that the electron moves initially perpendicular to the conductor and the helical path ensues due to the magnetic field, the conductor becomes the axis around which the electron rotates.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Lorentz Force
In the realm of electromagnetism, the Lorentz Force is a crucial concept to grasp for understanding how charged particles like electrons behave in a magnetic field. Its role cannot be overstated, particularly when dealing with scenarios involving magnetic fields and moving charges. The Lorentz Force is mathematically represented as \( \mathbf{F} = q(\mathbf{v} \times \mathbf{B}) \), where:
  • \( \mathbf{F} \) is the force exerted on the charged particle.
  • \( q \) stands for the electric charge of the particle, which in this case of an electron, is negative.
  • \( \mathbf{v} \) is the velocity of the particle.
  • \( \mathbf{B} \) denotes the magnetic field.

The force is always perpendicular to both the velocity of the particle and the magnetic field, leading to a circular motion if the initial velocity is perpendicular to the magnetic field. For a positively charged particle, the direction of the force is straightforward; however, for negatively charged particles like electrons, the direction is reversed, adding a twist to the path they will follow.
Right-Hand Rule
The Right-Hand Rule is a simple yet powerful tool used to determine the direction of the magnetic force on a moving charge. It provides a visual and tactile way to grasp the interaction between currents and magnetic fields. To apply the Right-Hand Rule:
  • Point your thumb in the direction of the conventional current (positive to negative).
  • Your fingers will naturally curl in the direction of the magnetic field lines.

This technique helps in visualizing how the magnetic field circulates around the conductor, forming concentric loops. In scenarios involving electrons, remember that they have a negative charge, flipping the direction of the force determined by the rule. By comprehending this rule, you can easily forecast the path of any moving charged particle in a magnetic environment.
Helical Motion
Helical motion is a fascinating result of the constant interplay between a charged particle's velocity and an external magnetic field. When an electron is ejected perpendicularly from a current-carrying conductor, it experiences a force that continually nudges it off its straight path. This psychedelic dance results in a helical or spiral trajectory.

Here's how helical motion unfolds:
  • The initial velocity of the electron is at a right angle to the magnetic field emanating from the conductor.
  • The magnetic field applies a continuous sideways force, creating a curved path.
  • This constant deflection causes the electron to follow a screw-like or helical path around the conductor.
  • The axis of rotation is parallel to the direction of the conductor.

In broad terms, this spiral motion occurs because the electron's velocity can be broken into components parallel and perpendicular to the magnetic field. The perpendicular component keeps changing direction, causing circular motion, while the parallel component remains unaffected, pushing the electron along the axis of the helical path.

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Most popular questions from this chapter

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