How objects become charged by friction, attraction and repulsion, sparking, and electric fields. Physics only content.
You can study this deck without signing up — your progress is kept in this browser. An account saves it properly, syncs it across devices, and lets you edit the cards.
1.How does an insulator become charged?
By friction. When two insulators are rubbed together, electrons are transferred from one to the other.
2.Which particles move when an object becomes charged?
Electrons only. Protons are held in the nuclei and do not move.
3.What charge does an object gaining electrons have?
A negative charge.
4.What charge does an object losing electrons have?
A positive charge.
5.What happens between two objects with the same charge?
They repel each other.
6.What happens between two objects with opposite charges?
They attract each other.
7.What kind of force is this?
A non-contact force, because the objects do not need to touch.
8.Why do charges not build up on a metal held in your hand?
Metal is a conductor, so the charge flows away through you to earth.
9.Why can a charged rod attract small pieces of paper?
The charge on the rod causes the charges in the paper to be attracted or repelled slightly, so the near side is oppositely charged and attracts.
10.What is an electric field?
A region where a charged object experiences a force.
11.Where is an electric field strongest?
Closest to the charged object, and it gets weaker as distance increases.
12.How is the direction of an electric field shown?
By arrows on field lines, pointing away from a positive charge and towards a negative charge.
13.What do the field lines around an isolated positive charge look like?
Straight lines radiating outwards in all directions.
14.What causes a spark?
A large potential difference builds up, and the electric field becomes strong enough to make the air conduct.
15.Why can sparks be dangerous?
They can ignite flammable vapours or dust, and give an electric shock.
16.How is the risk of sparking reduced when refuelling an aircraft?
The aircraft and the fuel tanker are earthed, so charge flows away rather than building up.
17.Why do you sometimes get a shock from a car door?
Friction as you slide across the seat charges you, and the charge flows to earth through the metal door when you touch it.
18.Why does rubbing a balloon on your hair make it stick to a wall?
The balloon becomes charged, which induces an opposite charge in the surface of the wall, so they attract.
19.Why can only insulators hold a static charge?
In a conductor the charge would immediately flow away, so it cannot build up on the surface.
20.What is meant by earthing?
Providing a conducting path for charge to flow safely to the ground.
You remember far more by trying to recall an answer than by reading it. Run these as flashcards and the ones you keep getting wrong will come back more often.
Start studyingOr see the other Electricity decks.