A Small Daily Lesson in Physics

What happens to electrons in any charging process? What happens to protons?

The electrons move/are transferred, the protons do nothing.

How is an object charged by induction? How about conduction?

In induction, a charged object is brought near the object to be charged causing a separation of charge, then some method of grounding to transfer the electrons. In conduction, a charged object touches the object to be charged causing electrons to be transferred.

What is polarization?

The separation of charge.

Suppose that a metal box is charged. How will the charge concentration at the corners differ from the concentration on the flat part?

It will be greater concentrated at the corners than the flat parts.

If 3 resistors are connected in a series circuit, what is the same for all resistors?

The current in the resistors.

If 3 resistors are connected in a parallel circuit, what is the same for all resistors?

The potential energy.

What do the following formulas mean:

a. F = kq1q2/d^2

This is Coulomb's law, so force overall = (the constant * charge 1 * charge 2) divided by the distance between the two, squared.

b. E = f/q = kQ/d^2

Energy = force/charge, or energy = (the constant * the big force) divided by the distance between the two, squared.

c. V = PE/q

Voltage = Potential Electricity/the force. Self-explanatory.

d. V = IR

Voltage = Current * Resistance, also seen as I = V/R

e. P = VI

Power = Voltage * Current

f. Req = R1 + R2

The total amount of Resistance in a series circuit = the sum of all resistors.

g. 1/Req = 1/R1 + 1/R2

The inverse of the total amount of Resistance in a parallel circuit = the inverse of resistor 1 + the inverse of resistor 2 + etc…

What is a positive/negative ion?

When an atom has too many/too few electrons and becomes positively or negatively charged.

What is meant by saying charge is conserved?

Electrons are not made or destroyed.

What’s the difference between a conductor and an insulator?

A conductor allows electrons to freely flow. An insulator resists the flow of electrons.

How is charging by friction different than charging by induction?

When charged by friction, the charger is physically touched to the object that one wants to charge, and electrons physically transfer over. When charging by induction, the charger doesn’t touch the item that one wants to charge, but the electrons come close enough to cause a separation of charge.

What occurs when an object is “grounded?”

It is supplied a path to the ground, which serves as a giant pool of electrons.

What defines the positioning of “the arrows” in a diagram of an electric field?

These arrows show where a positive test charge would go if it were in the field of the object. Remember, opposites attract.

Does current flow through a circuit or across it? How about voltage?

Current flows through a circuit, not across it. However, voltage does not flow, it is established across the circuit.

What is voltage also known as?

Electric Potential Difference. Not to be confused with PE, which is found by V=PE/q.


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