Coulomb's law

Question 1

Two small charged spheres carry 3 µC and 3 µC and are 0.5 m apart. What is the size of the force between them, in N? (F = k q₁ q₂ ÷ r², k = 8.99 × 10⁹ N m²/C², 1 µC = 10⁻⁶ C; give 2 decimal places)

Answer N

Question 2

How is the electrostatic force different from gravity?

• A. It is always weaker
• B. It only acts on metals
• C. It can attract or repel; gravity only attracts
• D. It does not depend on distance

Question 3

The distance between two charges is multiplied by 3. By what factor does the electrostatic force change? (Give 4 decimal places.)

Answer 

Question 4

Two small charged spheres carry 5 µC and 6 µC and are 0.1 m apart. What is the size of the force between them, in N? (F = k q₁ q₂ ÷ r², k = 8.99 × 10⁹ N m²/C², 1 µC = 10⁻⁶ C; give 2 decimal places)

Answer N

Question 5

Two positive charges are moved closer together. What happens to the force between them?

• A. the force decreases
• B. the force becomes zero
• C. the attractive force increases
• D. the repulsive force increases

Question 6

Both charges are multiplied by 2 and the distance is unchanged. By what factor does the force change?

Answer 

Question 7

Two small charged spheres carry 3 µC and 3 µC and are 0.1 m apart. What is the size of the force between them, in N? (F = k q₁ q₂ ÷ r², k = 8.99 × 10⁹ N m²/C², 1 µC = 10⁻⁶ C; give 2 decimal places)

Answer N

Question 8

How is the electrostatic force different from gravity?

• A. It is always weaker
• B. It does not depend on distance
• C. It only acts on metals
• D. It can attract or repel; gravity only attracts

Question 9

Both charges are multiplied by 4 and the distance is unchanged. By what factor does the force change?

Answer 

Question 10

Two small charged spheres carry 5 µC and 2 µC and are 0.5 m apart. What is the size of the force between them, in N? (F = k q₁ q₂ ÷ r², k = 8.99 × 10⁹ N m²/C², 1 µC = 10⁻⁶ C; give 2 decimal places)

Answer N

Question 11

How is the electrostatic force different from gravity?

• A. It only acts on metals
• B. It is always weaker
• C. It does not depend on distance
• D. It can attract or repel; gravity only attracts

Question 12

The distance between two charges is multiplied by 3. By what factor does the electrostatic force change? (Give 4 decimal places.)

Answer 

Question 13

Two small charged spheres carry 1 µC and 1 µC and are 0.5 m apart. What is the size of the force between them, in N? (F = k q₁ q₂ ÷ r², k = 8.99 × 10⁹ N m²/C², 1 µC = 10⁻⁶ C; give 2 decimal places)

Answer N

Question 14

How is the electrostatic force different from gravity?

• A. It can attract or repel; gravity only attracts
• B. It is always weaker
• C. It does not depend on distance
• D. It only acts on metals

Question 15

The distance between two charges is multiplied by 2. By what factor does the electrostatic force change? (Give 4 decimal places.)

Answer 

Question 16

Two small charged spheres carry 5 µC and 3 µC and are 0.5 m apart. What is the size of the force between them, in N? (F = k q₁ q₂ ÷ r², k = 8.99 × 10⁹ N m²/C², 1 µC = 10⁻⁶ C; give 2 decimal places)

Answer N