Physics Chapter 12.1: Coulomb's Law

Questions and Answers

What is Coulomb's law primarily concerned with?

The behavior of charges in a vacuum

The relationship between electric charges and magnetic fields

The motion of electric charges

The force between two point charges (correct)

Which of the following correctly describes the relationship defined by Coulomb's law?

Force is inversely proportional to the product of the charges

Force is inversely proportional to the square of the distance between charges (correct)

Force is directly proportional to the distance between charges

Force is directly proportional to the product of the charges (correct)

What happens to the force between two like charges according to Coulomb's law?

It remains constant regardless of distance

It repels each other (correct)

It increases with the distance between them

It attracts each other

What is the constant of proportionality (k) in Coulomb's law dependent on?

The type of medium between the charges Signup and view all the answers

In a vacuum, what is the approximate value of the permittivity of free space ( ext{epsilon}_0)?

8.85 * 10^{-12} Nm^2/C^2 Signup and view all the answers

What is the effect of distance on the force between two point charges as described by Coulomb's law?

Force decreases with increased distance Signup and view all the answers

For two different point charges in free space, if the distance between them is halved, how does the force between them change?

It becomes quadruple the original force Signup and view all the answers

Which of the following best represents the mathematical expression of Coulomb's law?

$F = k \frac{q_1q_2}{r^2}$ Signup and view all the answers

Study Notes

Charges and Their Interaction

Two types of electric charges exist: positive (protons) and negative (electrons).
Like charges repel each other, while unlike charges attract each other.

Historical Context

Charles Coulomb conducted the first measurement of electric force in 1874.
His experiments led to the formulation of Coulomb's law.

Coulomb's Law

Coulomb's law quantifies the force between two point charges.
The force (F) is directly proportional to the product of the magnitudes of the charges (q1 and q2).
The force is inversely proportional to the square of the distance (r) between the charges.
Mathematically expressed as:
- F ∝ (q1 * q2) / (r²)
- F = k * (q1 * q2) / (r²)

Force Characteristics

F is the magnitude of the mutual force acting on the charges.
Force acts along the line that connects the two charges.
'k' represents the constant of proportionality.

Coulomb's Constant

The value of 'k' varies with the medium between charges and the unit system used.
For free space and SI units:
- ( k = \frac{1}{4 \pi \epsilon_0} )
- ( \epsilon_0 ) is the permittivity of free space, valued at ( 8.85 \times 10^{-12} , \text{Nm}^2/\text{C}^2 ).
Substitute to find ( k = 9 \times 10^9 , \text{N m}^2/\text{C}^2 ).

Coulomb's Force in Free Space

The expression for Coulomb's force in free space becomes:
- ( F = \frac{1}{4 \pi \epsilon_0} \cdot \frac{q1 \cdot q2}{r^2} )

Description

Explore the principles of Coulomb's Law in this quiz. Learn how electric charges interact and discover the historical context behind the quantitative measurement of electric forces conducted by Charles Coulomb. Test your knowledge of fundamental concepts such as like and unlike charges.