# College physics

posted by .

Two 2.4 cm diameter disks spaced 1.5 mm apart form a parallel-plate capacitor. The electric field between the disks is 4.3×10^5 V/m.
What is the voltage across the capacitor?
How much charge is on each disk?
An electron is launched from the negative plate. It strikes the positive plate at a speed of 2.3×10^7 m/s. What was the electron's speed as it left the negative plate?

• College physics -

E x d is the voltage
d is the plate separation

Use Gauss' Law or Q = CV for the charge

The change in kinetic energy equals e V

• College physics -

5

## Similar Questions

1. ### Physics

Two parallel plate capacitors have circular plates. The magnitude of the charge on these plates is the same. However, the electric field between the plates of the first capacitor is 2.2e5 N/C, while the field within the second capacitor …
2. ### College Physics

A 12.0- A 12.0- A 12.0-V battery remains connected to a parallel plate capacitor with a plate area of 0.204m^2 and a plate separation of 3.14mm . What is the charge on the capacitor?
3. ### Physics

The figure shows an electron entering a parallel-plate capacitor with a speed of 5.65×106 . The electric field of the capacitor has deflected the electron downward by a distance of 0.618 at the point where the electron exits the capacitor.
4. ### Capacitor

A parallel plate capacitor with plates of area 320 cm.^2 is charged to a potential difference V and is then disconnected from the voltage source. When the plates are moved 0.3 cm. farther apart, the voltage between the plates is increased …
5. ### physics

A parallel-plate capacitor is formed from two 1.0{\rm cm} \times 1.0{\rm cm} electrodes spaced 2.8{\rm mm} apart. The electric field strength inside the capacitor is 1.0\times10^{6}{N/C}} part a What is the charge (in {\rm nC}) on …
6. ### Physics

A q = +3.00 mC test charge is placed inside a constant uniform electric field created in a parallel plate capacitor connected to a battery of unknown voltage.   The capacitor is made of two parallel plates each with area equal to …