Problem 1: A Parallel plate capacitor with neoprene rubber (dielectric strength=
ID: 1521759 • Letter: P
Question
Problem 1:
A Parallel plate capacitor with neoprene rubber (dielectric strength=12x10^6 V/m, k=6.7) and has a capactiance of 100pF.
a. If the plate separation of the capacitor is 100um, what is the surface area of the plates?
b. What is the maximum operating voltage of the capacitor?
c. what is the maximum energy that can be stored on teh capactitor?
d. If we had a capacitor of the same dimensions with air between the plates ( dielectric strength =3X 10^6 V/m, k=1 ) what would be the maximum operating voltage?
Problem 2:
One electron collides elastically with a second electron initially at rest. After the collison, the radii of their trajectories are 1.40 cm and 3.00cm. The trajectories are perpendicular to a uniform magnetic field of 0.0390 T. Determine the energy in KeV of the incident electron.
Explanation / Answer
2)
here by using the formula
v = -e * B * r / m
use the conservation of the energy
KE = 0.5 * m * v1^2 + 0.5 * m * v2^2
KE = 0.5 * m * ( - e * B * r1 /m)^2 + 0.5 * m * ( - e * B * r2 / m)^2
= (0.5 * e^2 * B^2 / m ) * (r1^2 + r2^2)
= ((0.5 * (1.602 * 10^-19 * 0.039)^2) / (9.1 * 10^-31) )* (0.014^2 + 0.03^2)
= 2.35 * 10^-14 J
then in eV
= 2.35 * 10^-14 * 6.24 * 10^18 = 146.64 KeV