12.2 Flashcards
Electric Potential and Potential Difference
What makes electrons move?
Potential Difference, which is a difference in electric pressure along the conductor.
What is potential difference?
Difference in electric pressure along the conductor.
What produces potential difference?
A cell or a battery.
How does a battery/cell generate potential difference?
The chemical action within a cell generates the potential difference across the terminals of the cell, even when no current is drawn from it. When the cell is connected to a conducting circuit element, the potential difference sets the charges in motion in the conductor and produces an electric current. In order to maintain the current in a given electric circuit, the cell has to expend the chemical energy stored in it.
Define potential difference.
We define the electric potential difference between two points in an electric circuit carrying some current as the work done to move a unit charge from one point to the other.
Potential difference formula plus definition.
Potential difference (V) between two points = Work done (W )/Charge (Q)
The potential difference between two points is described as the work done to move a unit charge from one point to another.
Potential difference SI unit.
The SI unit of electric potential difference is volt (V) named after Alessandro Volta (1745 –1827), an Italian physicist.
Define the unit of potential difference.
One volt is the potential difference between two points when 1 joule of work is done to bring 1 coulomb of charge from one point in the conductor to the other.
What is a volt?
Volt is the SI unit of potential difference.
One volt is the potential difference between two points in an electrical conductor when it takes 1 joule of work to move 1 coulomb of charge from the first point to the second.
1 V = 1 J / 1 C
1 volt = 1 joule / 1 coulomb
State the formula for potential difference.
V = W/ Q
What is used to measure the potential difference?
The potential difference is measured by means of an instrument called
the voltmeter. The voltmeter is always connected in parallel across the
points between which the potential difference is to be measured.
How do ammeters and voltmeters differ?
Ammeters measure current and are always connected in series. They must have very low resistance so the readings stay accurate.
Voltmeters measure the potential difference across two points in a circuit and they are always connected in parallel across the points where the potential difference is to be measured.
How much work is done in moving a charge of 2 C across two points having a potential difference 12 V?
V = W/Q
=> W= VQ
here,
V= 12V
Q= 2 C
so 12*2= 24 J
24 Joules of work is done.
Name a device that helps to maintain a potential difference across a
conductor.
A cell or a battery.
What is meant by saying that the potential difference between two points is 1 V?
This means that 1 Joule of work is done to move a charge of 1 Coulomb from one point to another.
