electrostatics

It's a cathode ray tube - It's the Electrostatics chapter, passage X, Q.65 (P 149). On occasion, the electrons are made to pass through the plates undeflected. If the electrons enter the region between the plates with the same direction, but with excessive velocity: A) they will be deflected...

The dielectric constant K of an unknown material is measured as a function of temperature. What can explain the sharp rise and subsequent slow decay of K as the temperature increases? Graph is K vs T : it has a sharp increase at T1 and then starts to decrease A- The solid material melts at T1...

If charge -Q of mass m is kept on y axis at large distance from the center, then it will execute oscillatory and periodic motion but if it is released very close to the origin then it will execute SHM .I want to know why?