91影视

a) Initial orientation of the electric dipole i,${胃}_i={20.0}^0$

b) Final orientation of the electric dipole f, ${胃}_f={20.0}^o$

c) Strength of the uniform external electric field $\stackrel{鈫�}{E}=3.00x{10}^6\text{N/C}.$

d) The electric dipole moment, $p=1.60x{10}^{鈭�27}\text{C.m}$

Using the concept of an electric dipole, we can get the potential energy of the dipole. This determines the change in the potential energy of the system.

Formula:

Potential Energy of an Electric Dipole is given by:$U=鈭�\stackrel{鈫�}{p}.\stackrel{鈫�}{E}=鈭�pEcos胃$ (i)

Where,

$\stackrel{鈫�}{p}$and $\stackrel{鈫�}{E}$are the dipole moment and Electric field

From the given data and the figure, we know that the initial and final angles of orientation ${胃}_i={70.0}^0$are${胃}_f={110.0}^o$, we can get the change of the potential energy using equation (i) as follows:

$\begin{array}{c}螖U=鈭�pE(cos70.0掳鈭�cos110掳)\\ =鈭�\left(1.60x{10}^{鈭�27}\text{C.m}\right)\left(3.00x{10}^6\text{N/C}\right)\left(0.684\right)\\ =鈭�3.28x{10}^{鈭�21}\text{J}\end{array}$

Hence, the value of the potential energy is.$鈭�3.28x{10}^{鈭�21}\text{J}$