PHYS-153 Mid-Term Definitions and Concepts

What is Charge?

An electric charge, possessed by an object, that causes particles to experience a force when placed in an electromagnetic field. Often expressed in Coulomb (C).

What is Coulombs Law?

The electrostatic force between two types of charge.

Equation: F= (Kq1q2) \ r²

Coulombs Constant: 8.99 × 10^9 Nm²/c²

What is Electrostatic Force?

The amount and direction of attraction or repulsion between two charged bodies.

Is Electrostatic Force inversely proportional to the square of the distance?

Yes, if one doubles the distance (1/(2r)²), force becomes one-forth (1/4r) as strong.

Is Electrostatic Force directly proportional to the quantity of the charges?

Yes, if one doubles both, the product of the charges (and force) quadruples.

Would the magnitude of force be affected by the following statement: q1 = 4q2.

It would affect individual field strengths, but not the magnitudes of force.

(As Newton’s Law states: force of 1 on 2 equals force of 2 on 1).

What would happen if there were two positively charged conductors?

Like charges would repel and move to their respective sides. The force would decrease due to the effective separation between charges.

As distance Increases, the electrostatic force _________.

Decreases

As distance Decreases, the electrostatic force __________.

Increases

What is Electric Field?

The amount of electric force exerted into space from a point charge. It is expressed in N/C.

What is Electric Potential?

Potential energy per unit charge (Voltage).

Equation: V= Kq\r

What is Potential Difference?

The change in voltage (V).

OR

The change in potential energy of a charge moved from one point to another, divided by the charge.

What are Equipotential Lines?

A line where the electric potential (V) is constant.

In an opposite dipole configuration, where is electric field the strongest?

Between the two dipoles, where field lines are the most dense.

In a parallel plate configuration, where is electric field the strongest?

The field is uniform. Therefore, the electric field has the same strength and direction between the two plates. However, edges do tend to fringe.

What would happen if one were to increase the potential difference in an opposite dipole configuration?

The electric field strength would increase. The field lines would become denser and more compact.

What would happen if one were to increase the potential difference in a parallel plate configuration?

The density and strength of the electric field would increase. However, its uniform field may fringe more so.

A uniform field…

has the same strength and direction at every point.

What would happen if a positive charge moved closer to a negative charge?

The potential energy of the positive charge would decrease.

What would happen if a negative charge was forced to travel in the same direction as an electric field line?

The potential energy (U) would increase. It would be moving against its own natural direction, so external positive work would be necessary.