A parallel-plate capacitor of capacitance 20 µF is fully charged by a battery of 12 V. The battery is then disconnected. A dielectric slab of K = 4 is slipped between the two plates of the capacitor:

(a) Find the change in potential energy of the capacitor.

(b) Does the potential energy increase or decrease? Explain

The electric potential a distance r from a small charge is proportional to what power of the distance from the charge? a. r^-1 b. r c. r^-2 d. r^2

Scientist have use computer models to create a series of maps that show how susceptible coastal cities in island countries are to the sea rising at different levels. the map shows that a 1 meter rise would swap cities all along the us eastern seaboard. a 6-meter sea level rise with sub merge a large part of florida. thermal expansion has already raise the oceans 10 to 20 centimeters the most likely cause, directly and indirectly, for such a rise in sea level is

An electron and a proton are held on an x axis, with the electron at x = + 1.000 m and the proton at x = - 1.000 m. part a how much work is required to bring an additional electron from infinity to the origin? express your answer with the appropriate units. part b if, instead of the second electron coming in from infinity, it is initially at x = + 20.00 m on the axis and is given an initial velocity of 100.0 m/s toward the origin, does it reach the origin? part c how close to the origin does it come?