Electric fields
What does an object with a charge have?
A object with a charge has an electric field has it.
How do you measure electric field lines for a 3D electric field?
An electrolytic tank can be used to plot the field lines of a 3D electric field. A tank is filled with water which has dissolved positive and negative ions in it. Electrodes are put into the water to create a positive charge at one end and a negative charge at the other end. A voltmeter is then used to find points where the potential difference is the same. From this both equipotentials and field lines can be plotted.
How do you measure electric field lines for a 2D electric field?
Conducting paper can be used to map out the electric field lines. The experiment is set up so that at one end of the page is a positive charge and on the other end is a negative charge. A voltmeter is then used to measure the potential difference at different points on the paper. Points with same potential difference can be joined together to show equipotential lines. Equipotential lines are always perpendicular to the field lines so you can map out the field lines as well on the conducting paper.
What else doe the force depend on if the point charges aren't in a vacuum?
Depends on the permitivitty of the material between them.
What are electric field lines?
Electric field lines are drawn to show the direction of the force acting on a positive coulomb of charge in an electric field.
What is the electric field strength?
Electric field strength is defined as the force per unit positive coulomb of charge. The field strength depends on where you are in the field.
What will the electric field lines look like for a negative point charge?
For a negative point charge the field lines point towards the point charge.
What will the electric field lines look like for a positive point charge?
For a positive point charge the field lines point away from the point charge.
What are the electric field lines for parallel plates?
For parallel plates the electric field lines go from the plate with more positive voltage to the plate with less positive voltage.
What happens to the force if the charges move further apart from each other?
The force decreases.
What is coulomb's law?
The force on a charge object in an electric field due to another charge over a distance r. The forced on a charged object in an electric field is either attractive or repulsive. The force on a charged object in an electric field is caused by the product of the two charges. The force on a charged object in an electric field is inversely proportional to the distance from centre to centre of the two charges. ( Inverse square law).
What is the path of positively charged particles and negatively charged particles once they enter an electric field?
The path of a charged particle in a electric field will bend depending of the charge of the particle. A charged particle that enters at right angles to the electric field will feel a constant parallel to the electric field lines. If the particle is positively charged then the force acts on it in the same direction as the field lines. If the particle is negatively charged then the force acts on it in the opposite direction as the field lines. This causes the particle to accelerate at right angles to the particle's original motion and so it follows a curved path (parabola).
