A molecular electric dipole has magnitude of dipole moment

PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Electric Force Field and Potential · Electric Force Field and Potential

Problem

3.0\times10^{-29}\,\text{C\,m}

. The dipole is kept fixed in vacuum with its axis along the positive

x

-direction and its centre at the origin. Consider the following points in space and answer the questions that follow. (i) Point

P

lies on the axis at a distance of

10\,\text{cm}

from the centre on the positive

x

-axis. Calculate the electric potential at

P

. (ii) Point

Q

is located at the same distance

10\,\text{cm}

from the centre but makes an angle of

60^{\circ}

with the dipole axis. Calculate the potential at

Q

. (iii) Find the ratio

V_P:V_Q

and comment on its numerical value. (iv) If the dipole is rotated through

180^{\circ}

about its centre, what will be the new sign (positive, negative or zero) of the potentials at

P

and

Q

? Justify your answer conceptually, without fresh calculation.