Question
Give an explanation about electric field lines and explain how they can be drawn.
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Answer
►Electric field lines are the pictorial representation of an electric field.
►Electric field lines were first described by a scientist named Michael Faraday.
►Let the point charge be placed at the origin. Draw vectors pointing along the direction of the electric field with their lengths proportional to the strength of the field at each point.
►Since the magnitude of electric field at a point decreases inversely as the square of the distance of that point from the charge from $\left( E =\frac{k Q }{r^2}\right)$ the vector gets shorter as one goes away from the origin, always pointing radially outward. Figure shows such a picture.
►In this figure, each arrow indicates the electric field, i.e., the force acting on a unit positive charge, placed at the tail of that arrow.
►Connect the arrows pointing in one direction and the resulting figure represents a field line. We thus get many field lines, all pointing outwards from the point charge.
►The magnitude of the field is represented by the density of field lines. E is strong near the charge, so the density of field lines is more near the charge and the lines are closer.
►Away from the charge, the field gets weaker and the density of field lines is less, resulting in well-separated lines.
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