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Lesson: Motion of a Charged Particle in Combined Electric and Magnetic Fields

Question Video: Combined Effects of Magnetic and Electric Fields on Charged Particle Motion

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Worksheet: Motion of a Charged Particle in Combined Electric and Magnetic Fields • 9 Questions

Q1:

An electron with a kinetic energy of 2.000 keV moves along a path that is equidistant from the surfaces of two parallel plates that are 1.00 cm apart and have a potential difference of 300 V. What is the strength of the uniform magnetic field acting parallel to the plates?

  • A T
  • B T
  • C T
  • D T
  • E T

Q2:

An electron in the cathode-ray tube of an old television moves at a speed of m/s in a direction perpendicular to Earth’s magnetic field, which has a magnitude of T in the region around the electron. Usually, televisions that use cathode-ray tubes are magnetically shielded so that electrons inside the tubes are not deflected by Earth’s magnetic field, but this television is not shielded. Instead, an electric field is applied perpendicular to the direction of Earth’s magnetic field and perpendicular to the direction of the electron’s velocity, which results in the electron moving in a straight line.

What is the magnitude of the applied electric field?

The applied electric field is produced between parallel plates separated by a 1.00 cm distance. What is the potential difference across the plates?

Q3:

A velocity selector uses both a magnetic field of magnitude 0.051 T and an electric field of magnitude V/m.

At what speed must a proton move in the selector to pass through it undeflected?

  • A m/s
  • B m/s
  • C m/s
  • D m/s
  • E m/s

At what speed must an alpha particle move in the selector to pass through it undeflected?

  • A m/s
  • B m/s
  • C m/s
  • D m/s
  • E m/s

At what speed must a singly ionized atom move in the selector to pass through it undeflected?

  • A m/s
  • B m/s
  • C m/s
  • D m/s
  • E m/s
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