Electric current and Potential Difference Flashcards
Define electric current.
An electric current is the rate of flow of charged particles.
What is the SI unit of current?
The SI unit of current is the ampere (A).
Explain how a solution of sodium chloride dissolved in water can conduct electricity.
- Dissolving sodium chloride in water produces positively charged sodium ions and negatively charged chlorine ions.
- The ions are mobile and will allow a electric current to flow through it.
What is the SI unit of charge?
The SI unit of charge is the coulomb (C).
What is the charge on an electron?
The charge on an electron is 1.6 x 10^-19 C.
What is the relationship between charge/C current/A and time/s.
Q = It
Define 1 coulomb.
1 coulomb is the quantity of charge that passes through any section of a conductor in 1 second when a current of 1 ampere is flowing. 1 C = 1 As
Explain what needs to be done in order for electrons to flow in a metal.
Energy must be supplied. In a simple circuit, an electric cell can be used to provide the energy needed to move the free electrons in the metal. The cell produces energy because of the chemical reactions taking place in it.
Describe electron flow.
Electrons flow from the negative end of the cell through the conduction to the positive end.
Describe conventional electric current.
This current flow is opposite in direction to electron flow. It can be thought of as going from the positive end of the cell through the conductor to the negative end.
How are electrical currents measured?
Electrical currents are measured using an ammeter.
How are ammeters connected in the circuit?
Ammeters are connected in series with the component.
What is an ideal ammeter?
An ideal ammeter has zero resistance.
Describe the energy changes that occur when charge passes through a filament lamp.
Energy is converted from electrical to light and thermal energy as it passes through the filament lamp.
Describe the energy changes that occur when charge passes through a resistor.
Energy is converted from electrical to thermal energy.
What cause an electric current to flow from one point to another.
A difference in electric potential between two points causes an electric current to flow from one point to another.
Define electric potential.
Electric potential at a point in an electric field is the work done in moving unit positive charge from infinity to that point.
What is the SI unit of electric potential and potential difference?
The SI unit of potential is the volt (V).
Define potential difference.
The potential difference between two points in a circuit is the word done in moving unit positive charge from one point to another.
How is potential difference measured.
Potential difference is measured with a voltmeter.
How is the voltmeter connected in a circuit?
A voltmeter is connected in parallel with the component whose potential difference is being measure.
What is an ideal voltmeter?
An ideal voltmeter has an infinite resistance.
What is the relationship between potential difference/V, work done/J and charge/C?
V = W/Q
Define 1 volt.
1 volt is defined as the potential difference between two points in a circuit when 1 joule is energy is converted when 1 coulomb of charge flows between the two points. 1 V = 1 J C^-1
