A charged particle having drift velocity of 7.5× 10^-4 m/s in an electric field of 3×10^-10V/m, has mobility in m^2 V^-1 s^-1

 [NEET-2020 ] a. 2.25×10^15      b. 25×10^6      c. 2.5×19^-6        d. 2.25 ×10^-15

A Spherical Conductor Of Radius 10 Cm Has A Charge Of 3.2 × 10–7 C Distributed Uniformly. What Is The Magnitude Of Electric Field At A Point 15 Cm From The Centre Of The Sphere?

   

Two concentric sphere kept in air have radii R & r . they have similar change and equal charge density σ. The electric potential at their common centre is? ( MHT - CET ~ 2014 )

  \[ a ) \frac { \sigma (R + r) } { \epsilon _{ o } } \]    \[ b ) \frac { \sigma (R - r) } { \epsilon _{ o } } \]    \[ c ) \frac { \si...