Question

Question #89b77

Answer 1

The 'line' is an arrow, meaning the field is a vector.

Explanation:

A vector has both size (or magnitude) and direction. As a field can point in different directions this information is also important.

Answer 2

The equation says that the electric field `vecE` is the following quotient: (the force, `vecF_E`, due to the electric field, on a test charge) divided by (the charge, q, of the test charge).

Explanation:

The definition of electric field from my copy of `Halliday*Resnick " Physics Part II"`:

If a positive test charge `q_o` is placed at point P and if an (electric) Force F acts on the stationary charge, an electric field E is present at P, where E is the vector satisfying the relation
F = `q_o` E

The Equation of the pic you included, with your symbols, is
`vecE = vecF_E/q`.
That equation is equivalent to the equation above from my college textbook.

• The `vecE` is the electric field. The units of `vecE` are Newtons/Coulomb.
• The `vecF_E` is the force that acts on a test charge due to the electric field it finds itself in. The unit of `vecF_E` is Newtons.
• The `q` is the charge on the test charge. The unit of q is Coulombs.

I hope this helps,
Steve