The electric field intensity at a point near a sphere of radius r and surface density of `rho` in a medium of dielectric constant K is

Options

A. `(4pi rho)/( k)`
B. `(2pi rho)/( k)`
C. `( pi rho)/(kr )`
D. `(pi rho)/(2 kr )`

Explanation

Torque ` tau = P E sin theta ~~ pE theta [theta ~~0]` M
Again , `tau =- I (d^(2) theta )/( d t ^(2) )`
` therefore pE theta =-(Id^(2) theta )/( dt ^(2)) or, ( d^(2) theta ) /( dt^(2) + p (E )/(I) =0`
comparing the above equation with the general equation of SHM ,
`omega ^(2) =pE )/(I ) ` or , omega =((pE )/(I ))^(1/2)`