A cavity of radius r is present inside a fixed solid dielectric sphere of radius R, having a volume charge density of `rho`. The distance between the centres of the sphere and the cavity is a. An electron is released inside the cavity at an angle `theta = 450` as shown. The electron (of mass m and charge –e) will take `((Psqrt(2)mrepsilon_(0))/(earho))^(1//2)` time to touc the sphere again. Neglect gravity. find the value of P:

Answer

B

Explanation

`F=eE=(epa)/(3e_0)`
`rsqrt2=1/2 F/m t^2`
`t=sqrt(6sqrt2 re_0 m)/(epa))`