8.1 Electric Charge and Electric Force

• Electric charge is a fundamental property of matter that causes it to experience a force when placed in an electromagnetic field
• Protons carry a positive charge.


  True
• Electrons are found in the nucleus of an atom.

  False
• Coulomb's Law describes the electric force between two point charges
• Arrange the properties of Coulomb's Law in a logical order:

  1️⃣ Electric force is directly proportional to the product of the charge magnitudes

  2️⃣ Electric force is inversely proportional to the square of the distance between the charges

  3️⃣ Electric force acts along the line connecting the two charges

  4️⃣ Electric force is attractive for opposite charges and repulsive for like charges
• What is the mathematical expression for Coulomb's Law?

  $F =$$k \frac{Q_{1} Q_{2}}{r^{2}}$
• The electric force is directly proportional to the product of the charge magnitudes.


  True
• Protons carry a positive charge.


  True
• What is the approximate value of the elementary charge (e)?

  1.602 \times 10^{-19} C</latex>
• Match the charge type with its carrier and interaction with like charges:

  Positive ↔️ Protons, Repel

  Negative ↔️ Electrons, Repel
• Order the steps in the example of charge conservation when a neutral object gains electrons:

  1️⃣ Neutral object gains electrons

  2️⃣ Object becomes negatively charged

  3️⃣ The object that lost electrons becomes positively charged

  4️⃣ Total charge in the system remains zero
• What does the variable $F$ represent in Coulomb's Law?


  Electric force
• The electric force is directly proportional to the absolute product of the charge magnitudes
• The formula for gravitational force is F_{g} = G \frac{m_{1} m_{2}}{r^{2}}
• Calculate the electric and gravitational forces between two protons with charges $+$$1.6 \times 10^{ - 19} C$ and masses $1.67 \times 10^{ - 27} kg$ separated by $1 \times 10^{ - 15} m$.


  $F_{e} \approx 2.3 N, F_{g} \approx 1.86 \times 10^{ - 34} N$
• Positive charges are carried by protons
• Match the variable with its symbol and unit:

  Electric Force ↔️ F ||| N

  Coulomb's Constant ↔️ k ||| N·m²/C²

  Charge Magnitudes ↔️ Q₁, Q₂ ||| C

  Distance between Charges ↔️ r ||| m
• Match the variable with its unit:

  Electric Force ↔️ N

  Coulomb's Constant ↔️ N·m²/C²

  Charge Magnitudes ↔️ C

  Distance between Charges ↔️ m
• Coulomb's Law describes the electric force between two point charges.


  True
• Two charges, +4 µC and +6 µC, are separated by 0.12 m. Calculate the electric force.

  15.0 N
• The electric force between two charges is attractive if they have opposite signs.

  True
• How does the distance between charges affect the electric force magnitude?

  Inversely proportional to r²
• The gravitational force between two protons is much weaker than the electric force at the same distance.


  True
• Electric charge is quantized and comes in discrete multiples of the elementary charge \(e\), which is approximately $1.602 \times 10^{ - 19}$
• Like charges repel each other, while opposite charges attract
• Electric charge is conserved in a closed system.


  True
• The Coulomb constant is approximately \(8.99 \times 10^9\) N⋅m^2/C^2.


  True
• Coulomb's Law describes the electric force between two point charges
• What is the approximate value of Coulomb's constant (k)?

  $8.99 \times 10^{9} N \cdot m^{2} / C^{2}$
• What is electric charge a fundamental property of?

  Matter
• Electric charge is quantized, meaning it comes in discrete multiples of the elementary charge.
• Like charges repel each other.


  True
• The total electric charge in a closed system remains constant.


  True
• The formula for Coulomb's Law is F = k \frac{|Q_{1} Q_{2}|}{r^{2}}
• What does the variable $r$ signify in Coulomb's Law?


  Distance between charges
• Calculate the magnitude of the electric force between two charges Q₁ = 2 \mu C</latex> and $Q₂ =$$- 3 \mu C$ separated by $r =$$0.1 m$.


  5.394 N
• The gravitational constant $G$ is approximately 6.67 \times 10^{ - 11} N m^{2} / kg^{2}</latex>.


  True
• What subatomic particle carries a positive charge?

  Proton
• What is the formula for Coulomb's Law?

  $F =$$k \frac{Q_{1} Q_{2}}{r^{2}}$
• Like charges repel each other, while opposite charges attract.


  True