A strip of tape is pulled off a roll and picks up charge. Is there an electric field around it?
Two strips of sticky tape are pulled off a roll, and both come away carrying charge. Hold one near the other, and it bends away. No contact anywhere.
The last lesson showed that any object with charge has an electric field around it. This lesson says what that field does to charged objects inside it.
Now consider one charged strip hanging inside the other strip's electric field. The hanging strip carries charge, and it sits inside an electric field.
The strip experiences a force. Here, the force is a push away. The strips never touched. The electric field already filled the space between them.
The force can be a push or a pull. Either way, no contact is needed. A charged dust grain inside the field experiences a force. And a charged scrap of foil inside the field experiences a force too.
A charged ribbon hangs inside the electric field of a charged balloon. Does the ribbon experience a force?
Write down the fact:
In an electric field, any object with charge will experience a force.
The ribbon carries charge, and it hangs inside the balloon's field.
Yes: the ribbon experiences a force.
A charged piece of glitter sits inside an electric field. Does it experience a force?
Must the ribbon touch the balloon before the force acts?
Write down the fact:
The electric field already fills the space around the balloon.
So the field acts on the ribbon where it hangs.
No: the force acts without contact.
Must two charged objects touch before one can push or pull the other?
That is why the tape strip bent: it carries charge, it sat inside an electric field, so it experienced a force.
A charged foam ball hangs from a thread inside an electric field, touching nothing. Which statement is true?
A charged plate hangs above a charged seed husk. The husk lifts before they touch. Why can the plate act on the husk across the gap?
Which of the following will experience a force in an electric field?