The Hall Effect & Velocity Selector by Tasfia Wasima Rahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa Presentation for Physics Class en-us 2021-10-31 13:01:04 UTC 2025-09-28 00:54:15 UTC hello@padlet.com THE HALL EFFECT tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856612858 2021-10-31 13:07:24 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856612858 Edwin Hall tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856621055 American physicist who discovered the Hall effect in 1879]]> 2021-10-31 13:13:10 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856621055 Why do we need it? tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856650812
  • The Hall effect is applied to a simple device, known as Hall probe, which is used to get an instant measure of the magnetic flux density of a magnetic field.
  • It is so sensitive and accurate that it can be used to measure the magnetic field of the Earth as well
    • ]]>     2021-10-31 13:34:26 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856650812     The Hall probe tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856656469
  • probe is made from a semiconductor material
  • semiconductors have a smaller number of electrons, so they have a larger drift velocity compared to metals, for the same value of current [ I=nAvq ]
    • ]]>     2021-10-31 13:38:08 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856656469     Understanding how it works tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856733066
  • a current is supplied through the sides of the probe
  • the probe is placed on a magnetic field such that its large face is perpendicular to the field lines
  • this results in the electrons being pushed of to one side of the probe
  • negative charge accumulates on one side, which causes an electric field to be formed
  • equilibrium is established between FB and FE
  • a constant potential difference, called the Hall voltage, forms between the two sides of the probe
    • ]]>     2021-10-31 14:28:03 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856733066     Deriving the equation for Hall voltage tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856804669 2021-10-31 15:15:12 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1856804669 Conditions tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1857153933 to get a good VH reading:
    • 't' needs to be small, i.e probe should be very thin
    • 'n' needs to be small, i.e probe should be made out of a semiconductor
    ]]>     2021-10-31 20:12:42 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1857153933     effect of changing B field on VH tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1857159139 2021-10-31 20:18:12 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1857159139 tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1857754731 2021-11-01 03:33:29 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1857754731 Velocity Selector tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858025066 2021-11-01 06:24:40 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858025066 tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858026467 2021-11-01 06:25:36 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858026467 Effect of holes on polarity of VH tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858036794
  • 'holes' are electric charge carriers with a positive charge
  • when holes are used in the Hall probe instead of electrons, the polarity of VH does not change
    • ]]>     2021-11-01 06:33:12 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858036794     tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858314003
  • two parallel charged plates, providing constant electric field strength E, are placed in a vacuum
  • a magnetic field of flux density B is applied to the region at right angles
  • charged particles travel through this region with different speeds
  • the magnetic force FB is greater in particles with greater speeds since FB = Bev
  • for particles with the desired speed v, FE and FB cancel out, so they move past undeflected
    • ]]>     2021-11-01 09:35:12 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858314003     Used in tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858338958
  • mass spectrometer
  • electron microscopes
    • ]]>     2021-11-01 09:52:58 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858338958     Finding the velocity v tasfiawasimarahman https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858343992 2021-11-01 09:56:22 UTC https://padlet.com/tasfiawasimarahman/ltsbzrgana14l8sa/wish/1858343992