IB SL Physics Charged oil drop in a uniform electric field

A tutorial sheet on a charged oil drop in a uniform electric field is given below.

1. An charged oil drop of mass 0.1 g is held at rest in a vertical uniform electric field between two oppositely charged parallel metal plates. The potential difference between the plates is 1000.0 V, the top plate is positive and the plates are 2.0 cm apart. Find the magnitude of the charge on the oil drop.
2. X-rays are directed on the air between the plates causing the charge on the drop to be halved. Find the new net force acting on the oil drop.
3. The drop falls from rest and reaches a terminal speed. Find the drag force acting on the oil drop.
4. Sketch graphs showing the (a) distance travelled by the oil drop (b) speed of the oil drop and (c) acceleration of the oil drop, as it falls from rest in part (3).
5. When the potential difference between two oppositely charged parallel metal plates is V1 an oil drop falls downwards with a terminal speed u1. When the potential difference between the plates is V2 the oil drop moves upwards with a terminal speed u2. Find the charge on the drop.

IB HL Physics Dielectrics and capacitors

A tutorial sheet with dielectric questions is given below.

1. What is a dielectric?
2. What does dielectric constant mean?
3. Plastic has a dielectric constant of 2.8. Find the permittivity of plastic.
4. A block of plastic is placed in a uniform electric field. Is the electric field strength in the plastic greater than, equal to or less than the electric field strength outside the plastic?
5. A block of dielectric fills the space between the parallel plates of a capacitor that is connected to a source of constant emf. Is the capacitance increased, stays the same or decreased when the dielectric is inserted?
6. A block of dielectric fills the space between the parallel plates of an isolated charged capacitor. Is the capacitance increased, stays the same or decreased when the dielectric is inserted?