What is a field?
A field is a quantity that has a value at every point in space. Examples include wind speed, temperature, light intensity, position, gravitational field, and electric field.
What is the electric field?
Electric fields are emitted by objects with an excess charge (positive or negative). They add as vectors.
Does the magnitude of the electric field get smaller or larger as you move away from a charged object?
The magnitude (absolute numerical value) of the electric field decreases as you move away from a charged object. The value is inversely proportional to the square of the distance from the charged object.
Where does the electric field due to a negatively charged object point?
The electric field points towards a negatively charged particle.
Where does the electric field due to a positively charged object point?
The electric field points away from a positively charged particle.
How does the electric field relate to the electric force? Use a description, not an equation.
A charged particle interacting with the electric field of another particle experiences an electric force.
How does the electric field relate to the electric force? Use an equation and describe the terms of the equation.
The force (F) between two particles is equal to the electric field (E) of one particle times the charge (q) of the second particle.
F = qE
What is the symbol for the electric field? Is the electric field a scalar or a vector?
The symbol for the electric field is E. The electric field is a vector.
What are the units of an electric field?
The units for an electric field are N/C (Newtons per Coulomb).
Can an object interact with its own electric field to experience a force?
No. Every charged particle has an electric field, but only experiences a force by interacting with the field of a different particle.
What does it mean for an object to have a linear charge density?
It means the excess charges on the object are spread out in a line, such as on a thin wire. A linear charge density (lambda) is equal to the amount of charge per meter, C/m.
What does it mean for an object to have a surface charge density?
It means the excess charges on the object is spread out over a two dimensional surface, such as the surface of a table or a sphere. A surface charge density (sigma) is equal to the amount of charge per square meter, C/m^2.
What does it mean for an object to have a volume charge density?
It means the excess charges on the object are spread out over a three dimensional volume, such as throughout a cube or a sphere. A surface charge density (rho) is equal to the amount of charge per cubic meter, C/m^3.
Where will you find excess charge located on an insulator?
Excess charge on an insulator will be spread throughout the volume.
Where will you find excess charge on a conductor?
Excess charge on a conductor will be located on the surface of the object only.
The equation for Coulomb’s Law only applies to which kind of objects?
Point particles.
You can use the Brute Force equations to find the electric field around which three kinds of extended objects?
A line of charge, a ring of charge, and a disk of charge.
In the Brute Force equations for the electric field of extended objects, what does the variable y mean?
y is the distance from the center of the line/disk/ring to the place where the field is being calculated.
The Brute Force equations only work if you’re measuring a field where?
Directly above or below the center of the line, disk, or ring.
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Chapter 1: Units and Conversions20
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Chapter 5: Electric Forces31
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Chapter 5: Electric Fields19
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Chapter 6: Gauss's Law15
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Chapter 7: Electric Potential16
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Chapter 9: Current and Resistance16
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Chapter 10: DC Circuits15
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Chapter 8: Capacitance9
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Chapter 11: Magnetic Forces and Fields10
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Chapter 15: Oscillations2
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Chapter 16: Waves0
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Chapter 17: Sound0
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Chapter 1: The Nature of Light0
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Chapter 2: Geometric Optics and Image Formation0
