Question

This is for an electric field mapping lab.

Explain the pattern of a field found inside a "Faraday's ice pail"

Diagrams appreciated!

Answer 1

Faraday's ice pail experiment:

Principle of electric fields in Ice pail experimement-

"When the charged object  is enclosed inside the conductive container, all the field lines extending from the object must terminate on the inside surface of the container"

• As the charge is lowered inside the container, the outside of the container is becoming increasingly charged.
• Once the object is well inside the lip of the container the charge detector levels off and registers a constant charge, even if the object is lowered further. The charge on the outside of the container is the same polarity as that on the object.
• If the charge detector is touched to the inside surface of the container, it is found to be charged with opposite polarity.

As the charge is lowered more and more into the container, more electric field lines terminates inside the container and as it finally reaches the lowest position, all the electric fields get terminated inside the container.(As shown in Fig D)

Note: Though it is an open surface, still it is treated as closed due to excessive large area of the top surface