# electrcity

1. ### Capacitance and induced charge of a spherical Capacitor + dielectric

I) For the first part I used: $V = - \int E ds = \int_a^c \frac{1}{4\pi\epsilon_0} Q /r^2 dr+ \int_c^{c+d} \frac{1}{k} \frac{1}{4\pi\epsilon_0} Q /r^2 dr + \int_{c+d}^b \frac{1}{4\pi\epsilon_0} Q /r^2 dr$ And by using $C = Q/V$ We get an answer which is somehow large for writing here...

28. ### Could nothing happen when fork in socket

Hi right now I do not have school but I was thinking about what my chemistry teacher said last year. he was telling us about electrons and how they move from negative to positive. he said something along the line of: lets you would put a fork in a wall socket and by chance you first hit the...
29. ### Stargazing Lightning ball - please help me to analyze this rare video

Hi, Some time ago I was looking for lightning ball videos on youtube. I observed some strange phenomenon recorded on one of the videos. Before a lightning ball is created, some "dark" ball is coming from above and then it immediately changes to the lightning ball which is moving at different...
30. ### B Conductors and electrons

Why is a sea of electrons present in a conductor? I read some where that they absorb a energy at normal temperatures and use it to get free electrons , but then why do they absorb energy while insulators don't??