Question

An infinite plane sheet of positive charge has surface charge density sigma.A metallic ball of mass m and charge +Q is attached to a point and tied to thread A on the sheet PQ.What is the angle theta made by the string with the plane sheet ?what quantity is dipole moment? Either scalar or vector?

Answer 1

the dipole moment is vector quantity as it comes from vector multiplication of magnetic field and area(both vectors) and current. a solution for the angle is we have to assume the equilibrium condition i.e. thread has made a theta angle with the sheet then t cos(theta)=mg so t=mg/cos(theta) and also tsin(theta)=f(qe) so by solving (replacing the value of tension(t) from an equation ) u will get theta=tan^-1(sigma*Q/epsilon).

Answer 2

Answer:

Explanation:

Tcos  theta=mg......................(1)

T sin theta= Eq      ..................(2)

where E = sigma/2 epsilon.

on dividing it we get

tan theta=sigma* q/2*epsilon*m*g