Question

select True or False for the follwing statements about electric field lines.
A positive point charge released from rest will initially accelerate along an E-field line.
E-field lines make circles around positive charges.
E-field lines point inward toward negative charges.
E-field lines may cross.
E-field lines point outward from positive charges.
Where the E-field lines are dense the E-field must be weak.
E-field lines do not begin or end in a charge-free region except at infinity.

Answer 1

Concepts and reason

The concept required to solve this problem is the properties of electric field lines.

Use the properties of the electric field lines to identify the statement is true or false.

Fundamentals

The properties of electric field lines are as follows:

The electric field lines point away from positive charge and towards a negative charge.

The electric field line direction is given by a force on positive test charge.

The greater number density of electric field lines or closer the lines greater the magnitude of electric field.

The electric field lines never intersect or cross each other.

Like charges repel and unlike charges attract.

(1)

The electric field line points in the direction of the force experienced by a positive test charge. A positive point charge therefore will experience an electric force along the electric field. The electric force on the point charge will accelerate the charge along the electric field.

(2)

The electric field lines travels in straight line and they do not form curved paths. So, the electric field lines do not make circles around the positive charge.

(3)

The electric field lines always travels away from the positive charge and they travels towards the negative charge.

(4)

The electric field lines never cross each other. The electric field lines if cross each other at some point would mean there are two directions in which a test positive charge experiences net force in the electric field. The net electric force always points in only one direction at a point on a charge.

(5)

The electric field direction is given by a force on positive test charge. Like charges repel so the positive charges repel the positive test charge. The electric force points away from the positive charges so the electric field lines point outward from positive charges.

(6)

The greater number density of electric field lines or closer the lines greater the magnitude of electric field. So, denser the electric field lines stronger is the field.

(7)

The electric field direction is given by a force on positive test charge. There is no electric force in a charge free region on a positive test charge.

So, the electric field lines do not begin or end in a charge free region except at infinity.

Ans: Part 1

The statement a positive charge released from rest will initially accelerate along the electric field lines is true.