38 Questions
What is the strength of an electric field defined as?
the force applied per unit charge on an object
What are the units of electric field strength, and are they interchangeable?
NC-1 or Vm-1, and yes, they are interchangeable
What is the direction of an electric field?
the direction a positive charge would accelerate at that point
What is Coulomb's law, and what does it state about the electrostatic force between two point charges?
Coulomb's law states that the electrostatic force between two point charges is proportional to the product of their charges and inversely proportional to the square of the distance between them
What is the constant of proportionality in Coulomb's law, and what is its value?
k = 8.99 × 10^9 Nm^2 C^-2
What is the permittivity of free space, and what is its value?
ε₀ = 8.85 × 10^-12 Fm^-1
What is the formula for the electrostatic force between two point charges, according to Coulomb's law?
F = kQq / r^2
What is the shape of the gravitational field around a point mass?
Radial
What is the direction of the force experienced by a positive charge in an electric field?
Repulsive
What is the relationship between the force of gravity and the distance between two objects?
Inversely proportional to the square of the distance
What is the characteristic of a uniform electric field?
No dependence on position
What is the relationship between the electric field strength and the distance from a point charge?
Inversely proportional to the square of the distance
What is the work done on a charge in an electric field?
The product of the force and the distance over which the force acts
What is the characteristic of the gravitational force between two objects?
Always attractive
What is permittivity, and what is it used to define in a material?
Permittivity is a constant that defines the ability of a material to become polarized and store charge.
What is the permittivity of free space, and why is it the lowest value possible?
The permittivity of free space is the permittivity of a vacuum, and it is the lowest value possible because there is no matter in a vacuum to become polarized.
How can the permittivity of a material be written in terms of the permittivity of free space?
The permittivity of a material can be written as a constant, the relative permittivity, 𝜀𝜀𝑟𝑟, multiplied by the permittivity of free space.
What is the purpose of introducing a small test charge when calculating the electric field of a point charge?
The purpose of introducing a small test charge is to determine the electric field strength on the test charge without causing the point charge to move.
What formula can be used to calculate the electric field strength of a point charge?
The formula is 𝐸𝐸 = 𝐹𝐹 / (𝑞𝑞 𝑄𝑄) = 1 / (4𝜋𝜋𝑟𝑟 2 𝜀𝜀0)
What is the similarity between gravitational and electric fields?
Both gravitational and electric fields are fields that describe the force of attraction between objects.
Why is it useful to explore the concept of a field by comparing gravitational and electric fields?
It is useful to explore the concept of a field by comparing gravitational and electric fields because it helps to highlight the similarities and differences between the two.
What is the electric potential at a single point defined as?
The work done per unit charge to bring a positive charge from infinity to that point.
What is the relationship between the electric potential difference and the electric field?
V = Ed
Why can't the equation V = Ed be applied to non-uniform fields?
Because the electric field must be constant over the distance the charge moves.
What is the electric potential difference between two points A and B?
VB - VA
What is the definition of the electric potential difference between two points?
The work done per unit charge in moving a charge from one point to another in the field.
What is the electric potential at infinity often defined as?
0
What is the electric field strength in the case of parallel plates?
V/d
What is the electrical energy defined as?
The work done by a force over a distance.
What is the formula for the work done in moving a point charge from infinity to a radius r?
W = Qq / (4πr²ε₀)
What is the electrical potential energy needed to move a point charge from infinity to a radius r?
Qq / (4πr²ε₀)
What is the electric potential defined as?
The electrical potential energy per unit charge.
What is the formula for the electric potential at a point due to a point charge?
V = Q / (4πrε₀)
What is the significance of the graph on the right above?
It shows the relationship between electric potential and distance from a point charge.
What is the unit of electric potential?
Volts (V)
What is the relationship between electric potential and distance from a point charge?
The electric potential decreases as the distance from the point charge increases.
What is the importance of the concept of electric potential?
It allows us to calculate the energy required to move a charge from one point to another.
How is the electric potential energy related to the electric field?
The electric potential energy is the energy required to move a charge in an electric field.
Test your understanding of electric field strength, its definition, and unit. This quiz also covers Coulomb's law, which explains the forces between point charges. Learn how to calculate the force applied per unit charge and more!
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