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# Charged spheres

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1. A thin, spherical, conducting shell of radius R is mounted on an insulating support and charged to a potential of -125V. An electron is then fired directly toward the center of the shell, from point P at distance r from the center of the shell ( r>>R). What initial speed Vo is needed for the electron to just reach the shell before reversing direction?

2. Sphere 1 with radius R1 has positive charge q. Sphere 2 with radius 2R1 is far from sphere 1 and initially uncharged. After the separated spheres are connected with a wire thin enough to retain only negligible charge, (a) is potential V1 of sphere 1 greater than, less than, or equal to potential V2 of sphere2? What fraction of q ends up on (b) sphere 1 and (c) sphere 2? (d) What is the ratio p1/p2 of the surface charge densities of the spheres?

https://brainmass.com/physics/energy/charged-spheres-148804

#### Solution Preview

1. A thin, spherical, conducting shell of radius R is mounted on an insulating support and charged to a potential of -125V. An electron is then fired directly toward the center of the shell, from point P at distance r from the center of the shell ( r>>R). What initial speed Vo is needed for the electron to just reach the shell before reversing direction?

Solution :

-125V Vo
R e q = -1.6x10-19C
m = 9.1x10-31 kg

r << R
Insulating support

As the electron approaches the negatively charged spherical shell, it slows down due to the repulsive force from ...

#### Solution Summary

A step by step solution is provided. The expert examines charged spheres.

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