A water molecule perpendicular to an electric field has 1.40*10-21 J more potential energy than a water molecule aligned with the field. The dipole moment of a water molecule is 6.2*10-30Cm.

What is the strength of the electric field?

Express your answer with the appropriate units.

The strength of the electric field is 2.258 x 10⁸ N/C

Explanation:

Potential energy = - p*ECosθ

where;

d is the dipole moment

E is the electric field

θ is the angle of inclination

→When the water molecules is perpendicular to the field, θ = 90° and potential energy = p*ECosθ = d*ECos0 = 0

Total potential energy = 0 + 1.40*10⁻²¹J, since it is 1.40*10⁻²¹J more

→When the water molecules is aligned to the field, θ = 0°

potential energy = - p*ECosθ

dipole moment, p = 6.2*10⁻³⁰Cm

= - (6.2*10⁻³⁰) * (E) Cos0

0 + 1.40*10⁻²¹ J = - (6.2*10⁻³⁰) * (E),

E = (1.40*10⁻²¹ J) / (6.2*10⁻³⁰)

E = 2.258 x 10⁸ N/C

Therefore, the strength of the electric field is 2.258 x 10⁸ N/C