2019 Gen Physics final review #1, Electricity and Magnetism

Which of the following is true of two unlike charges? (One positive and one negative)

• They neutralize each other

• They attract each other

• They repel each other

• It cannot be determined what will happen

When are electrical forces strongest? (MARK 2 CORRECT ANSWERS!!)

• When the charges are close together

• When the charges are far apart

• When there is more charge

• When there is less charge

• The electrical force is not affected by distance

According to Coulomb's law, which of the following are true? (MARK 2 CORRECT ANSWERS!!)

• The electric force is inversely proportional to the square of the distance between the charges. (eg. double distance = 1/4 force)

• The electric force is directly proportional to the distance between the charges. (eg. Double distance, 2 x force.)

• The electric force is directly proportional to the amount of the charge. (eg. double charge, 2 x force)

• The electric force is directly proportional to the square of the amount of charge. (eg. double charge, 4 x force)

Two charges are separated by a certain distance, if the magnitude of each charge is tripled, what will happen to the force between the charges?

• triple the force

• 1/3 the force

• 9 times the force

• 1/9 the force

• none of these! Charge does not affect force!

Two charges are separated by a certain distance, if the magnitude of each charge is cut in half, what will happen to the force between the charges?

• half the force

• 1/4 the force

• double the force

• quadruple the force

• none of these! Charge does not affect force!

Two charges are separated by a certain distance. If the distance between the charges is double, what happens to the force?

• cuts to half the original force

• cuts to 1/4 the original force

• double the force

• quadruple the force

• Nothing! The electrostatic force is not related to distance!

Two charges are separated by a certain distance. If the distance between the charges is cut in half, what happens to the force?

• cuts to half (1/2) the original force

• cuts to 1/4 the original force

• double (2x) the force

• quadruple (4x) the force

• Nothing! The electrostatic force is not related to distance!

If you pet your dog, and it becomes negatively charged (his hair stands up all over due to it) what must happen to you?

• You must become positively charged because you gave some of your electrons to the dog.

• You must also become negative because you generated new electrons.

• Your charge did not change

Which of the following are true of gravitational and electrical forces? (MARK TWO CORRECT ANSWERS!!)

• Gravitational forces can attract and repel things, just like electrical forces.

• Both gravitational forces and electrical forces follow the inverse square law.

• Unlike gravitational forces, electrical forces can both attract and repel.

• Gravitational forces are stronger than electrical forces overall.

What happens to electrons in insulators?

• They move from atom to atom.

• They are bound with one atom only, but can move around the atom.

• They cannot move, even around their own atom.