H210 Electric Fields (AI) Flashcards
What is the definition of an electric field?
A region of space where an electric charge experiences an electric force.
How is electric field strength at a point defined?
The electric force exerted per unit positive charge placed at that point.
What does the direction of an electric field indicate?
The direction of force on a positive charge.
What is the formula for Coulomb’s law?
F = (1 / (4πε₀)) * (Q₁Q₂ / r²)
What does E = (1 / (4πε₀)) * (Q / r²) represent?
The electric field strength of a point charge in free space or air.
What is the relationship between electric field strength and potential difference?
E = ΔV / d
What is electric potential defined as?
The work done per unit positive charge in bringing a small test charge from infinity to that point.
True or False: Electric field lines can intersect.
False.
How do electric field lines behave in relation to charges?
They start on positive charges and end on negative charges.
What units are used for electric field strength E?
[N C⁻¹] or [V m⁻¹].
What is the electric force experienced by a charge q in an electric field E?
Fₑ = qE
What does the electric field strength E indicate in a uniform electric field?
It is constant at every point.
What happens to electric charges in a conductor at electrostatic equilibrium?
They reside entirely on the conductor’s surface.
What is the electric potential energy U of a charge at a point?
U = QV
What is the significance of the electric potential at infinity?
It is defined as zero.
What is the significance of the permittivity of free space (ε₀)?
It is a constant, approximately 8.85 × 10⁻¹² C² N⁻¹ m⁻².
What does the term ‘uniform electric field’ refer to?
An electric field where the strength is constant throughout.
Fill in the blank: The electric potential due to a point charge is given by V = _______.
Q / (4πε₀r)
What is the electric potential energy U of a system of two point charges Q₁ and Q₂?
U = (Q₁Q₂) / (4πε₀r)
How does a Faraday Cage function?
It shields its contents from external electric fields.
What is the effect of a uniform electric field on charged particles?
It causes them to accelerate uniformly.
What is the direction of electric field lines in relation to electric potential?
From higher electric potential to lower electric potential.
What is the relationship between electric force and gravitational force?
Electric force can be attractive or repulsive, while gravitational force is always attractive.
What is the formula for electric potential energy stored between two isolated point charges?
U = (Q1 * Q2) / (4πε0r)
What is the electric potential energy when another charge Q2 is brought from infinity to a distance r away from the center of Q1?
U = Q * V = Q * (1 / (4πε0r)) * Q1
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?
Electric potential at point X = V = (1 / (4πε0 * 0.25)) * 6.0 × 10^-6
What is the electric potential at a point Y, 50 cm from the surface of the same spherical conductor?
Electric potential at point Y = V = (1 / (4πε0 * 0.50)) * 6.0 × 10^-6
What is the change in potential energy of a +10 μC charge moving from point X to point Y?
Change in potential energy = q * (VY - VX)
What is the electric potential of a system of multiple point charges?
The total electric potential Vtotal = V1 + V2 + V3
How is the electric potential energy of a charge q placed at a point due to multiple point charges calculated?
Utotal = q * Vtotal
In Example 7, what are the two charges q1 and q2?
q1 = -6.0 nC and q2 = 3.0 nC
What is the potential at point O in Example 7?
Potential at O is calculated from the contributions of q1 and q2
What is the relationship between electric field strength and electric potential?
E = -dV/dr
What does the negative sign in the equation E = -dV/dr indicate?
It indicates that the direction of electric field strength points towards lower potential
What is the electric potential change when moving along an equipotential line?
No work is done when moving along an equipotential line
What is the principle of conservation of energy for electrons accelerated in an electric field?
The kinetic energy gained is equal to the work done by the electric field
What is the formula for the electric field strength E between two charged parallel plates?
E = ΔV/d
What is the key difference between electric and gravitational fields?
Electric fields can be attractive or repulsive, while gravitational fields are always attractive
What is Coulomb’s Law?
F = (1 / (4πε0)) * (Q1 * Q2) / r^2
What is the formula for gravitational force?
F = G * (M1 * M2) / r^2
What do equipotential lines represent in an electric field?
Equipotential lines are lines joining points that have the same potential
In the context of electric fields, what does the term ‘field strength’ refer to?
Field strength is the force per unit charge experienced by a small positive test charge
What is the significance of the potential difference (ΔV) in the context of electric circuits?
ΔV is the work done per unit charge in moving a charge between two points
How does electric potential energy relate to the position of a charge in an electric field?
Potential energy increases as a charge moves against the electric field
What happens to electric field lines in the presence of a charged conductor?
Electric field lines leave a conducting surface at right angles
