Coulomb's law

Question 1

How is the electrostatic force different from gravity?

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

Question 2

One charge is multiplied by 3 and the distance is unchanged. By what factor does the force change?

Answer 

Question 3

Two small charged spheres carry 4 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 4

How is Coulomb's law similar to Newton's law of gravitation?

• A. Both depend on mass
• B. Both are inverse square laws
• C. Both are unaffected by distance
• D. Both forces are always attractive

Question 5

One charge is multiplied by 3 and the distance is unchanged. By what factor does the force change?

Answer 

Question 6

Two small charged spheres carry 4 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 7

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 8

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

Answer 

Question 9

Two small charged spheres carry 2 µC and 6 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 10

Why don't we notice electrostatic forces between everyday objects most of the time?

• A. They only act in space
• B. Most objects are electrically neutral, with equal positive and negative charge
• C. Air blocks them
• D. Electrostatic forces are very weak

Question 11

One charge is multiplied by 3 and the distance is unchanged. By what factor does the force change?

Answer 

Question 12

Two small charged spheres carry 5 µC and 2 µC and are 0.3 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 13

How is Coulomb's law similar to Newton's law of gravitation?

• A. Both are unaffected by distance
• B. Both are inverse square laws
• C. Both forces are always attractive
• D. Both depend on mass

Question 14

One charge is multiplied by 4 and the distance is unchanged. By what factor does the force change?

Answer 

Question 15

Two small charged spheres carry 3 µC and 3 µC and are 0.2 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 16

Why don't we notice electrostatic forces between everyday objects most of the time?

• A. Air blocks them
• B. Electrostatic forces are very weak
• C. They only act in space
• D. Most objects are electrically neutral, with equal positive and negative charge