22 Electric fields Flashcards
what is the no1 rule for charges?
like charges repel
unlike charges attract
what are electrical conductors?
objects which can conduct electricity
they have free electrons to carry the charge
What is an electrically insulating material?
An electrical insulator is a material that cannot conduct electricity
What piece of apparatus is used to detect charge?
A gold leaf electroscope
What is an electric field line?
The path followed by a positive test charge
What is the electric field strength, E?
The electric field strength at a point in the field is the defined as the force per unit charge on positive test charge placed at that point
What is the formula for E?
E=F/Q
What are the characteristics of the electric field between two parallel plates?
The field lines are:
Parallel to each other
At right angles to the plate.
From the positive plate to the negative plate
What is the formula for E between two parallel plates?
E=V/d
What is electric potential?
The electric potential to certain position in any electric field is defined as the work done by unit positive charge on a positive test charge when it is moved from infinity to that point
What is an equipotential?
A surface of constant potential.
A test charge moving along and equipotential has constant potential energy.
What is potential gradient?
The change of potential per unit change of distance in a given direction
What is the electric field strength equal to? (negative.)
E is equal to the negative of the potential gradient
What is the formula for potential gradient?
dV/dx X
What is Coulomb’s law of force?
For two point charges at a distance r apart, the force between the two charges is given by the equation F = Q1Q2/4piE0r^2
