H213 Electric Fields (AI)

Question 1

What is the definition of an electric field?

Answer 1

A region of space where an electric charge experiences an electric force.

Question 2

How is electric field strength at a point defined?

Answer 2

The electric force exerted per unit positive charge placed at that point.

Question 3

What does the direction of an electric field indicate?

Answer 3

The direction of force on a positive charge.

Question 4

What is the formula for Coulomb’s law?

Answer 4

F = (1 / (4πε₀)) * (Q₁Q₂ / r²)

Question 5

What does E = (1 / (4πε₀)) * (Q / r²) represent?

Answer 5

The electric field strength of a point charge in free space or air.

Question 6

What is the relationship between electric field strength and potential difference?

Answer 6

E = ΔV / d

Question 7

What is electric potential defined as?

Answer 7

The work done per unit positive charge in bringing a small test charge from infinity to that point.

Question 8

True or False: Electric field lines can intersect.

Answer 8

False.

Question 9

How do electric field lines behave in relation to charges?

Answer 9

They start on positive charges and end on negative charges.

Question 10

What units are used for electric field strength E?

Answer 10

[N C⁻¹] or [V m⁻¹].

Question 11

What is the electric force experienced by a charge q in an electric field E?

Answer 11

Fₑ = qE

Question 12

What does the electric field strength E indicate in a uniform electric field?

Answer 12

It is constant at every point.

Question 13

What happens to electric charges in a conductor at electrostatic equilibrium?

Answer 13

They reside entirely on the conductor’s surface.

Question 14

What is the electric potential energy U of a charge at a point?

Answer 14

U = QV

Question 15

What is the significance of the electric potential at infinity?

Answer 15

It is defined as zero.

Question 16

What is the significance of the permittivity of free space (ε₀)?

Answer 16

It is a constant, approximately 8.85 × 10⁻¹² C² N⁻¹ m⁻².

Question 17

What does the term ‘uniform electric field’ refer to?

Answer 17

An electric field where the strength is constant throughout.

Question 18

Fill in the blank: The electric potential due to a point charge is given by V = _______.

Answer 18

Q / (4πε₀r)

Question 19

What is the electric potential energy U of a system of two point charges Q₁ and Q₂?

Answer 19

U = (Q₁Q₂) / (4πε₀r)

Question 20

How does a Faraday Cage function?

Answer 20

It shields its contents from external electric fields.

Question 21

What is the effect of a uniform electric field on charged particles?

Answer 21

It causes them to accelerate uniformly.

Question 22

What is the direction of electric field lines in relation to electric potential?

Answer 22

From higher electric potential to lower electric potential.

Question 23

What is the relationship between electric force and gravitational force?

Answer 23

Electric force can be attractive or repulsive, while gravitational force is always attractive.

Question 24

What is the formula for electric potential energy stored between two isolated point charges?

Answer 24

U = (Q1 * Q2) / (4πε0r)

Question 25

What is the electric potential energy when another charge Q2 is brought from infinity to a distance r away from the center of Q1?

Answer 25

U = Q * V = Q * (1 / (4πε0r)) * Q1

Question 26

What is the electric potential at a point X, 25 cm from the surface of a spherical conductor of radius 25 cm carrying a charge of +6.0 μC?

Answer 26

Electric potential at point X = V = (1 / (4πε0 * 0.25)) * 6.0 × 10^-6

Question 27

What is the electric potential at a point Y, 50 cm from the surface of the same spherical conductor?

Answer 27

Electric potential at point Y = V = (1 / (4πε0 * 0.50)) * 6.0 × 10^-6

Question 28

What is the change in potential energy of a +10 μC charge moving from point X to point Y?

Answer 28

Change in potential energy = q * (VY - VX)

Question 29

What is the electric potential of a system of multiple point charges?

Answer 29

The total electric potential Vtotal = V1 + V2 + V3

Question 30

How is the electric potential energy of a charge q placed at a point due to multiple point charges calculated?

Answer 30

Utotal = q * Vtotal

Question 31

In Example 7, what are the two charges q1 and q2?

Answer 31

q1 = -6.0 nC and q2 = 3.0 nC

Question 32

What is the potential at point O in Example 7?

Answer 32

Potential at O is calculated from the contributions of q1 and q2

Question 33

What is the relationship between electric field strength and electric potential?

Answer 33

E = -dV/dr

Question 34

What does the negative sign in the equation E = -dV/dr indicate?

Answer 34

It indicates that the direction of electric field strength points towards lower potential

Question 35

What is the electric potential change when moving along an equipotential line?

Answer 35

No work is done when moving along an equipotential line

Question 36

What is the principle of conservation of energy for electrons accelerated in an electric field?

Answer 36

The kinetic energy gained is equal to the work done by the electric field

Question 37

What is the formula for the electric field strength E between two charged parallel plates?

Answer 37

E = ΔV/d

Question 38

What is the key difference between electric and gravitational fields?

Answer 38

Electric fields can be attractive or repulsive, while gravitational fields are always attractive

Question 39

What is Coulomb's Law?

Answer 39

F = (1 / (4πε0)) * (Q1 * Q2) / r^2

Question 40

What is the formula for gravitational force?

Answer 40

F = G * (M1 * M2) / r^2

Question 41

What do equipotential lines represent in an electric field?

Answer 41

Equipotential lines are lines joining points that have the same potential

Question 42

In the context of electric fields, what does the term 'field strength' refer to?

Answer 42

Field strength is the force per unit charge experienced by a small positive test charge

Question 43

What is the significance of the potential difference (ΔV) in the context of electric circuits?

Answer 43

ΔV is the work done per unit charge in moving a charge between two points

Question 44

How does electric potential energy relate to the position of a charge in an electric field?

Answer 44

Potential energy increases as a charge moves against the electric field

Question 45

What happens to electric field lines in the presence of a charged conductor?

Answer 45

Electric field lines leave a conducting surface at right angles