Electric Charge
Question:
What are the two types of electric charge?
Answer:
Positive (+) and negative (−)
Two charges are + and −. What will happen?
They attract.
What two types of interactions can electric force cause between charged objects?
Attraction and repulsion.
What is the region around a charged object where electric force can act?
An electric field.
Model:(+) (+) What will the two charges do?
Repel.
What happens when two objects have the same type of electric charge?
Answer
They repel.
Two charges are + and +. What will happen?
They repel.
Is electric force a contact force or a noncontact force?
A noncontact force.
Around a positive (+) charge, which direction do electric-field lines points?
Away from the positive charge.
Model:(−) (+) What will the two charges do?
Attract
What happens when two objects have opposite electric charges?
They attract.
Two charges are − and −. What will happen?
They repel.
Two charged objects affect each other even though they are not touching. What does this show about electric force?
Electric force can act at a distance.
Around a negative (−) charge, which direction do electric-field lines point?
Toward the negative charge.
A positive test charge is placed where an electric-field arrow points LEFT ←. Which direction is the electric force on the test charge?
Left. A positive test charge experiences force in the direction of the electric-field arrow.
Mystery Charge: A positive charge is repelled by an unknown charged object. What charge must the mystery object have?
Answer: Positive
A positive test charge is placed near another positive charge. Predict what will happen.
The positive test charge will move away from the other positive charge because like charges repel.
A charged balloon attracts small pieces of paper without touching them first. What type of force is causing the attraction?
Electric force.
In an electric-field model, what does it mean when the field lines are closer together?
The electric field is stronger in that region.
A negative test charge is placed where the electric-field arrow points RIGHT →. Which direction is the electric force on the negative charge?
Left. A negative charge experiences force opposite the direction of the electric-field arrow.
A negative charge attracts an unknown object that is known to be charged. What charge must the unknown object have? Explain.
Positive. Opposite charges attract.
A positive test charge is placed between a positive charge on the LEFT and a negative charge on the RIGHT. Predict the direction of the electric force on the test charge.
To the RIGHT, toward the negative charge. The positive charge repels it and the negative charge attracts it.
True or False — Explain: “Electric force can only act when two charged objects are touching.”
False. Electric force can act at a distance. A charged object creates an electric field around it, and another charge in that field can experience electric force.
A positive test charge is placed in an electric field. How can you use the field-line arrows to predict the direction of the electric force on it?
The positive test charge experiences electric force in the same direction that the field-line arrows point.
Who is correct? Mia says, “Electric-field arrows show the direction every charge will be pushed.” Noah says, “Electric-field arrows show the direction of force on a positive test charge.
”Noah is correct. Electric-field direction is defined as the direction of force on a positive test charge. A negative charge experiences force in the opposite direction.