Coulombs Law Quiz: Master Electric Forces

1. Coulomb’s law describes the force between:

Two magnets

Two electric charges

Two masses

Two sound waves

Coulomb’s law applies to electrostatic forces between charges. It is the electric analogue of an inverse-square interaction.

Explanation

Coulomb’s law applies to electrostatic forces between charges. It is the electric analogue of an inverse-square interaction.

2. The electric force between charges depends on both the amount of charge and the distance between them.

True

False

Larger charges produce stronger forces, while greater separation weakens the force. Distance has a strong effect because the relationship is inverse-square.

Explanation

Larger charges produce stronger forces, while greater separation weakens the force. Distance has a strong effect because the relationship is inverse-square.

3. If you double the distance between two charges, the force (qualitatively) becomes:

Twice as strong

Half as strong

About one-quarter as strong

Unchanged

Coulomb force scales like (1/r^2). Doubling (r) makes the force four times weaker.

Explanation

Coulomb force scales like (1/r^2). Doubling (r) makes the force four times weaker.

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5. Electric field at a point is best defined as:

Energy per unit time

Force per unit positive test charge

Charge per unit time

Voltage per unit resistance

Field describes how a charge would be pushed at that point. It is defined as (E = F/q) for a small positive test charge.

Explanation

Field describes how a charge would be pushed at that point. It is defined as (E = F/q) for a small positive test charge.

6. A positive test charge experiences force in the direction of the electric field.

True

False

Field direction is defined by the force on a positive charge. A negative charge feels force opposite the field direction.

Explanation

Field direction is defined by the force on a positive charge. A negative charge feels force opposite the field direction.

7. If the electric field is zero at a point, the net force on a small test charge there is:

Maximum

Zero

Infinite

Always attractive

Net force is (F = qE). If (E = 0), then net force is zero regardless of small test charge.

Explanation

Net force is (F = qE). If (E = 0), then net force is zero regardless of small test charge.

8. Electric forces from multiple charges add using the principle of superposition.

True

False

Each charge contributes its own force/field. The net effect is the vector sum of all contributions.

Explanation

Each charge contributes its own force/field. The net effect is the vector sum of all contributions.

9. A neutral conductor placed near a charged object is attracted mainly due to:

Magnetic induction

Charge redistribution (induced separation)

Neutron flow

Photon pressure only

Charges in the conductor rearrange, placing opposite charge closer to the external charge. The nearer attraction outweighs farther repulsion, giving net attraction.

Explanation

Charges in the conductor rearrange, placing opposite charge closer to the external charge. The nearer attraction outweighs farther repulsion, giving net attraction.

10. In electrostatic equilibrium, excess charge on a conductor resides on its ______.

Free charges move until the internal electric field is zero. This leads excess charge to settle on the surface.

Explanation

Free charges move until the internal electric field is zero. This leads excess charge to settle on the surface.

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11. Inside a conductor at electrostatic equilibrium, the electric field is zero.

True

False

If there were a field inside, charges would keep moving. Equilibrium is reached when internal field vanishes.

Explanation

If there were a field inside, charges would keep moving. Equilibrium is reached when internal field vanishes.

12. Which statement best matches Coulomb’s law behaviour?

Force increases with distance squared

Force decreases with distance squared

Force is independent of charge

Force depends only on temperature

Coulomb force weakens rapidly with distance as (1/r^2). This is why electrostatic effects drop off quickly with separation.

Explanation

Coulomb force weakens rapidly with distance as (1/r^2). This is why electrostatic effects drop off quickly with separation.

13. If you double one of the charges (distance unchanged), the force magnitude:

Halves

Doubles

Becomes one-quarter

Stays the same

Coulomb’s law force is proportional to (q1 * q2). Doubling one charge doubles the product and thus the force.

Explanation

Coulomb’s law force is proportional to (q1 * q2). Doubling one charge doubles the product and thus the force.

14. Electric field lines point away from positive charges and toward negative charges.

True

False

By convention, field lines show the direction a positive test charge would move. That means away from positive and into negative charges.

Explanation

By convention, field lines show the direction a positive test charge would move. That means away from positive and into negative charges.

15. The electric force between a positive and a negative charge is:

Repulsive

Attractive

Always zero

Depends only on mass

Opposite charges attract. Opposite signs produce attraction. This is a basic rule for electrostatic interactions.

Explanation

Opposite charges attract. Opposite signs produce attraction. This is a basic rule for electrostatic interactions.

16. Superposition applies to electric fields even when multiple charges are present.

True

False

Each charge creates a field independent of the others. The net field is the vector sum of the individual fields.

Explanation

Each charge creates a field independent of the others. The net field is the vector sum of the individual fields.

17. The strength of an electric interaction dropping as (1/r^2) is called an ______-square law.

Many fundamental interactions spread out over spherical surfaces whose area grows as (r^2). That geometric spreading leads to inverse-square behaviour.

Explanation

Many fundamental interactions spread out over spherical surfaces whose area grows as (r^2). That geometric spreading leads to inverse-square behaviour.

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18. Two charges are brought closer together. The magnitude of the force between them generally:

Decreases

Stays the same

Increases

Becomes negative

Smaller separation increases the (1/r^2) value, strengthening the force. This is true for both attraction and repulsion.

Explanation

Smaller separation increases the (1/r^2) value, strengthening the force. This is true for both attraction and repulsion.

19. A charged object can exert force on a neutral object because it can polarise the neutral object.

True

False

Polarisation creates separated charges inside the neutral object. The closer opposite charges experience a stronger force, leading to net attraction.

Explanation

Polarisation creates separated charges inside the neutral object. The closer opposite charges experience a stronger force, leading to net attraction.

20. Which statement is most accurate overall?

Charge only matters in circuits

Charge interactions explain both static effects and electric forces/fields

Charge is the same as mass

Charge cannot move in any material

Electric charge underlies electrostatics and current electricity. Understanding charge helps explain forces, fields, and many everyday phenomena.

Explanation

Electric charge underlies electrostatics and current electricity. Understanding charge helps explain forces, fields, and many everyday phenomena.

Coulombs Law Quiz: Test Your Knowledge Of Electric Forces

1. Coulomb’s law describes the force between:

2.

What first name or nickname would you like us to use?

2. The electric force between charges depends on both the amount of charge and the distance between them.

3. If you double the distance between two charges, the force (qualitatively) becomes:

4. The electric force between like charges is ______.

5. Electric field at a point is best defined as:

6. A positive test charge experiences force in the direction of the electric field.

7. If the electric field is zero at a point, the net force on a small test charge there is:

8. Electric forces from multiple charges add using the principle of superposition.

9. A neutral conductor placed near a charged object is attracted mainly due to:

10. In electrostatic equilibrium, excess charge on a conductor resides on its ______.

11. Inside a conductor at electrostatic equilibrium, the electric field is zero.

12. Which statement best matches Coulomb’s law behaviour?

13. If you double one of the charges (distance unchanged), the force magnitude:

14. Electric field lines point away from positive charges and toward negative charges.

15. The electric force between a positive and a negative charge is:

16. Superposition applies to electric fields even when multiple charges are present.

17. The strength of an electric interaction dropping as (1/r^2) is called an ______-square law.

18. Two charges are brought closer together. The magnitude of the force between them generally:

19. A charged object can exert force on a neutral object because it can polarise the neutral object.

20. Which statement is most accurate overall?