Ch 24: Capacitors & DielectricsWorksheetSee all chapters
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Ch 01: Units & Vectors
Ch 02: 1D Motion (Kinematics)
Ch 03: 2D Motion (Projectile Motion)
Ch 04: Intro to Forces (Dynamics)
Ch 05: Friction, Inclines, Systems
Ch 06: Centripetal Forces & Gravitation
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Ch 19: Kinetic Theory of Ideal Gasses
Ch 20: The First Law of Thermodynamics
Ch 21: The Second Law of Thermodynamics
Ch 22: Electric Force & Field; Gauss' Law
Ch 23: Electric Potential
Ch 24: Capacitors & Dielectrics
Ch 25: Resistors & DC Circuits
Ch 26: Magnetic Fields and Forces
Ch 27: Sources of Magnetic Field
Ch 28: Induction and Inductance
Ch 29: Alternating Current
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Ch 38: Quantum Mechanics

Concept #1: Parallel Plate Capacitors

Practice: Two circular plates of radius 2cm are brought together so their separation is 5mm. What is the capacitance of these plates?

Example #1: Point Charge Inside Capacitor

Practice: A 3 F capacitor is given a potential difference across its plates of 10 V. What is the charge built up on its plates? If the source of the potential difference across the plates is removed, but the plates maintain their charge, what is the new potential difference across the capacitor if the distance between the plates is doubled?

Additional Problems
A uniform electric field is established by connecting the plates of a parallel-plate capacitor to a 12-V battery. A) If the plates are seperated by 0.75 cm, what is the magnitude of the electric field in the capacitor? B) A charge of +6.24 x 10 -6 C moves from the positive plate to the negative plate. Find the change in electric potential energy for this charge.
The charge on the square plates of a parallel-plate capacitor is Q. The potential across the plates is maintained with constant voltage by a battery as they are pulled apart to twice their original separation, which is small compared to the dimensions of the plates. The amount of charge on the plates is now equal to (a) Q/2. (b) Q. (c) Q/4. (d) 2Q. (e) 4Q.
Two parallel-plate capacitors C1 and C2, are separated by vacuum. C1 plate has an area twice as large as C2, but the plates of C1 are separated by a distance 1/3 that of C2. What is the ratio of their capacitance (C1: C2)? A) 1:6 B) 6:1 C) 2:3 D) 3:2
Consider a parallel-plate capacitor constructed from two circular metal plates of radius R. The plates are separated by a distance of 1.5 mm. (a) What radius must the plates have if the capacitance of this capacitor is to be 1.0 μF? (b) When the capacitor is connected to a 12.0-V battery, what is the magnitude of the charge on each of the plates? (c) Find the energy stored in the capacitor.
A parallel plate capacitor has plates with area A = 350cm2 separated by a distance d = 1.5mm. What is the capacitance when the capacitor is filled with air?  
You reposition the two plates of a parallel-plate capacitor so that the distance between them doubles. There is vacuum between the plates. If the charges +Q and -Q on the two plates are kept constant in this process, which of the following statements is incorrect? A) The potential difference between the two plates doubles. B) The electric field between the two plates keeps the same. C) The potential energy stored in this capacitor doubles. D) The capacitance of this capacitor doubles. 
Each plate of a parallel-plate air capacitor has an area of 0.0010 m 2, and the separation of the plates is 0.050 mm. An electric field of 7. 4x10   6 V/m is present between the plates. The capacitance of the capacitor, in pF, is closest to: A) 180 B) 300 C) 240 D) 120 E) 360
The plates of a parallel-plate capacitor are 3.0mm apart, and each plate carries 75nC of charge. The electric field between the plates has a magnitude of 3.5 x 106V/m. The plates are in vacuum. a) What is the potential difference between the plates? b) What is the capacitance? c) What is the area of each plate?
Two parallel conducting plates separated by a distance d are connected to a battery of voltage  ε. What is correct if the plate separation is doubled while the battery remains connected? 1. The potential difference between the plates is doubled. 2. The potential difference between the plates is halved. 3. The capacitance is unchanged. 4. The electric charge on the plates is doubled. 5. The electric charge on the plates is halved.
The potential difference between the plates of a parallel plate capacitor with the plate separation of 6 mm is 60 V. What is the electric field between the plates of this capacitor?A) 500 V/mB) 1000 V/mC) 2000 V/mD) 60 V/m
State what will happen to the capacitance of a parallel plate capacitor if the following changes are made. Don’t compute anything, just state whether the capacitance will increase, stay the same or decrease. a) The voltage across the capacitor’s plates is doubled b) The distance between the capacitor’s plates are decreased by a factor of 2 c) The area of the capacitor’s plates is doubled