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25 Cards in this Set
- Front
- Back
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A neutron walks into a bar and asks for a drink. He asks the bartender,
"How much?" The bartender responds, "_____" |
"For you, no charge."
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Two atoms are walking down the street. One atom says,
"Damn, I think I lost an electron!" The other atom says, "Are you sure?" The first atom says, "_____" |
"Yeah, I'm positive!"
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Write the equation and units for:
ΔPE = ? |
Change in potential energy
ΔPE = qΔΦ Units: Joules (J) |
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Write the equation and units for:
ΔKE = ? (3 different equations) |
Change in kinetic energy
ΔKE = -ΔPE ΔKE = Work ΔKE = ½m[(v_final)² - (v_initial)²] Units: Joules (J) |
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If a charge is negative, what do we know about the direction of Force on the charge (q) and the direction of the Electric Field?
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If the charge (q) is negative, the direction of Force (F) is *opposite* the direction of the Electric Field (E).
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What is Coulomb's Law?
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An equation describing the electrostatic force between charges.
F_electricity = K∣q₁∣∣q₂∣ / r² Units: Newtons (N) |
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Define:
Dipole |
A pair of equal but opposite charges.
(i.e. they both have the same magnitude, but different sign (+/-)) |
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Define:
e What is it's value and units? |
e = elementary charge. The smallest amount of charge something can have.
e = 1.6 * 10-¹⁹ Units: Coulombs |
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All objects want their Potential Energy _____?
(raised/lowered) |
...lowered.
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What is the equation and units for:
F_on q = ? |
The force that (charge q) feels because it's in an Electric field.
F = qE |
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What does the Principle of Superposition tell us?
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To find the total force (F_t) on an object, sum all the individual forces acting on it.
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What are the units for:
Φ |
Joules / Coulomb
or Volts |
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What units are used for:
Potential Energy |
Joules
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What units are used for:
Kinetic Energy |
Joules
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What is the equation and units for:
E = ? |
E = Electric Field
The magnitude of an electric field created by a charge (Q). E = K*∣Q∣ / r² Units: Newtons / Coulomb (N/C) |
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Describe how Electric Field vectors are related to equipotentials.
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Electric field vectors are at right angles to equipotentials, and point *toward* the smaller potential.
Example from sheet 21, problem 1.d |
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What is the equation and units for:
Φ = ? |
Φ is Electric Potential (or just 'potential')
Φ = K*Q / r Units: Volts (V) |
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What is the equation and units for:
Quantized Charge (Q) = ? |
Q = n(+/-e)
Where 'n' is a positive whole number. |
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What is the value and units for:
Coulomb's Constant |
K = 9*10⁹
Units: N*m² / C² |
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True of False:
Potential has direction. |
False.
Potential is a scalar; it has no direction. |
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True or False:
The magnitude of an electric field has direction. |
False.
Magnitude is just a scalar, and has no direction. |
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Electric Field vectors always point _____ from a positive source charge, and _____ a negative source charge.
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...away...
...toward... |
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If work is positive, it's from a _____ force.
If work is negative, it's from a _____ force. |
...helping...
...hindering... |
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Define:
Equipotential |
A curve/surface at which every point is at equal potentials.
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What is the equation and units for:
F_electricity = ? |
Also known as "Coulomb's Law"
F_electricity = K∣q₁∣∣q₂∣ / r² Units: Newtons (N) |
