Electrostatic Potential and Capacitance

Topics in this chapter

• Electrostatic Potential And Fields
• Spherical Charge Distributions
• Dipole Potential And Interactions
• Capacitor Combinations And Networks
• Dielectrics In Capacitors
• Capacitor Energy And Transients

Cheat sheet

Practice questions

1. Question 1Q-2CCD39

   What is the amount of work done in moving a test charge of $2 \times 10^{-9}\text{ C}$ along an equipotential surface from a point A to a point B separated by a distance of $5\text{ cm}$?

   1. A.$10^{-10}\text{ J}$
   2. B.Zero
   3. C.$10^{-8}\text{ J}$
   4. D.$4\text{ J}$
   See the answer and solution
2. Question 2Q-5ECBCC

   A parallel plate capacitor with air between the plates has a capacitance $C$. If the distance between the plates is doubled and the space between them is filled with a dielectric medium of dielectric constant $K = 4$, the new capacitance will be:

   1. A.$2C$
   2. B.4C
   3. C.$C/2$
   4. D.$8C$
   See the answer and solution
3. Question 3Q-8527FB

   Four capacitors of capacitances $2\,\mu\text{F}, 4\,\mu\text{F}, 6\,\mu\text{F}$, and $12\,\mu\text{F}$ are connected in parallel. If the combination is connected across a $100\text{ V}$ supply, the total charge stored in the combination is:

   1. A.$2400\,\mu\text{C}$
   2. B.$1200\,\mu\text{C}$
   3. C.$600\,\mu\text{C}$
   4. D.$24\,\mu\text{C}$
   See the answer and solution
4. Question 4Q-8B62A6

   An electric dipole of dipole moment $P$ is placed in a uniform electric field $E$ with its axis making an angle of $60^{\circ}$ with the field. The potential energy of the dipole is:

   1. A.$-\frac{\sqrt{3}}{2}PE$
   2. B.$-\frac{PE}{2}$
   3. C.$\frac{PE}{2}$
   4. D.$-PE$
   See the answer and solution
5. Question 5Q-54D74E

   The electric potential at any point $(x, y, z)$ in space is given by $V = 3x^2 + y$, where $V$ is in volts and $x, y$ are in meters. The magnitude of the electric field at the point $(1\text{ m}, 2\text{ m}, 0\text{ m})$ is:

   1. A.$6\text{ V/m}$
   2. B.$7\text{ V/m}$
   3. C.$\sqrt{37}\text{ V/m}$
   4. D.$3\text{ V/m}$
   See the answer and solution