Quiz 4

• A parallel-plate capacitor of capacitance C has the area of plates A and distance between

  plates d. Capacitor is connected to the battery of voltage V, fully charged and then disconnected. A slab of dielectric material with dielectric constant 4 is then inserted into capacitor, completely filling region between plates. Potential difference on this capacitor:

  Decreases four times
• Metallic sphere of radius R is charged to the charge Q. It is connected by the conducting

  wire to another sphere, initially neutral with radius R/2. What is the charge on second

  sphere after the process of re-charging stops?

  Q/3
• Consider the parallel-plate capacitor charged to the charge Q and disconnected from a battery. If half of a charge is removed from plates, the capacitance of capacitor:

  Will stay the same
• Capacitor of capacitance C is fully charged and has charge Q. It is disconnected from a battery and connected to second capacitor, of capacitance 2C and initially not charged. When the system comes to equilibrium, what is the charge on the second capacitor?

  2Q/3
• Two parallel-plate capacitors have identical gaps between plates. The plates have form of ideal circles. The radius of plate of capacitor 1 it R, the radius of plate of capacitor 2 is 2R. If the capacitance of capacitor 1 is C, then capacitance of the second one is:

  4C