Induction Solenoids

Induction coils

0309181127

 

  • When current through a solenoid changes, a magnetic field is induced within the solenoid. If two solenoids are concentric with each other, the induced field in one solenoid produces a changing current in the other.
  • Connect a power supply to one solenoid and a galvanometer to the other.
  • Unless steel rod is inserted in innermost cylinder (shown above), induced magnetic field is too week to produce a noticeable effect. Steel rod greatly enhances effect.

Location

Solenoids: L01, section B-2

Galvanometer: L35, section F-3

Power supply: L35, section F-1

 

 

Lenz’s Law Pipe

 

Induction Pipe

  • Use Lenz’s law to explain extremely slow descent of neodymium
    magnet through copper pipe.
  • Hold pipe in a vertical orientation; drop magnet through
    top opening of pipe; watch descent through holes in pipe.
  • Try pipe with continuous slit to see difference in effect.
  • Use copper slug to show speed of descent of non magnetic object.

Location

  • Pipes located in L01, right-hand side between A2 and B1.
  • Magnet in L01, section B2.

 

Lenz’s Law Pendulum

 

Lenz's Law Pendulum demo picture

  • Purpose: Demonstrate the effect of eddy currents on motion of metal pendulum in strong B-field.
  • Pendulum accessories include two interchangeable copper plates, one of which is serrated. Serrated copper plate experiences little resistance to motion through magnetic field.
  • Located in L03

 

 

Current in Solenoid

 

Current in Solenoid demo picture

  • Purpose: Illustrate principles of electro-magnetic induction.
  • Send current through solenoid and measure direction of B-field
    using B-field indicator (magnaprobe). Place coil of wire in front of solenoid
    and quickly adjust current; galvanometer will indicate induced emf consistent
    with Lenz’s law.

Location

  • Solenoid and wire coil located in L01, section B2.
  • Power supply- L35, section F1;
  • magnaprobe- L35, section E4, top shelf
  • galvanometers- L35, section F3