Electric potentials?

DAMON

2015-09-27 3:58 pm

3. (a) Two spheres of radius r1 = 0.1m and r2 = 0.2m have potentials 1000 V and -400 V
respectively. They are very far apart so that we can assume that there is no electrostatic interaction
between the two spheres. Calculate the charges on the two spheres.

(b) If the two spheres are connected by a conducting wire, what will be the final potential and
charge on each sphere?

回答 (1)

麻辣

2015-09-28 3:09 am

✔ 最佳答案

3a.Two spheres of radius r1 = 0.1m and r2 = 0.2m have potentials 1000 V

and -400 V respectively. They are very far apart so that we can assume

that there is no electrostatic interaction between the two spheres.

Calculate the charges on the two spheres.

Q1 = V*r/k

= 1000*0.1/9*10^9

= 1/9*10^7

= 1.111 * 10^(-8) coul

Q2 = -400*0.2/9*10^9

= - 0.8889 * 10^(-8) coul

3b.If the two spheres are connected by a conducting wire, what will be

the final potential and charge on each sphere?

Q = Q1+ Q2 = 0.2222 * 10^(-8) coul

V1 = kQ/r1

= 9*10^9*0.2222*10^(-8)/0.1

= 200 volts

V2 = 9*10^9 * 0.2222 * 10^(-8)/0.2

= 100 volts

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