Electricity and Energy Flashcards
What are the two types of Electrical Charge?
Positive and Negative
What do like charges do?
Repel
(Positive Repels Positive)
(Negative Repels Negative)
What do opposite charges do?
Attract
(Negative attracts Positive)
(Positive attracts Negative)
Describe the model of an atom?
Contains Protons which have a positive charge, neutrons which have no charge and electrons which have a negative charge.
How do we charge materials?
Giving the material electrons which will make it negatively charged or by removing electrons to make it positively charged.
Electrons are the only thing that can do what?
Move
What is an electric current?
An electric current is a flow of negatively charged electrons.
An electric current flows from negative to positive
What is electric charge measured in?
Coulombs, C
Describe Ohms Law?
Voltage = Current x Resistance
V=IR
What do you call an opponent that obeys ohms law?
An ohmic component
As the voltage across a bulb increases, what happens to the current?
Current also increases
How can the resistance of a wire be altered?
Changing length, material or thickness?
Describe the difference in resistance when the wires factors are changed?
A long wire has a greater resistance than a short wire
A thick wire has a lower resistance than a thin wire
How do we calculate the total resistance in a series circuit?
RT= R1 + R2 = R3
How do we calculate the total resistance in a parallel circuit?
1/RT = 1/R1 + 1/R2
What is voltage?
The voltage is the energy provided for every coulomb of charge
What can voltage also be measured in?
Joules per Coulomb
What is the definition of the volt?
If 1 joule of work is done in moving 1 coulomb of charge between 2 points, the potential difference between the 2 points is 1 volt
What are some of the uses for Electrostatics?
Making photocopies removing dirt from air spraying car bodies Spraying crops cling film
Describe the terms insulators and conductors?
Insulators do not allow an electric current to flow through them
Conductors allow an electric current to flow through them
Explain Direct Current?
Direct Current flows from the negative side of the power supply to the positive side.
Batteries and cells provide a direct current
Explain Alternating Current?
An alternating current flows from one side of the power supply for a short period of time then travels to the other for a short period of time.
(Alternates Direction)
Mains supply provides an alternating current
What is the frequency of mains supply?
50Hz
What is mains voltage and mains peak voltage is?
230V
325V
A big resistance means what in relation to voltage?
Bigger share of the voltage?
When the temperature increases what happens to the resistance of the thermistor?
Resistance of thermistor decreases
When the light intensity increase what happens to the resistance of the L.D.R?
Resistance of L.D.R Decreases
What Equation links power, current and voltage?
P=IV
What does the power rating of an appliance tell us?
The rate at which electrical energy is used
What is the job of a fuse?
To protect the component from a large current?
What fuse is used when the power is less than 720W?
3A Fuse
What fuse is used when the power is greater than 720W?
13A Fuse
What are the forms of energy?
Heat, Light, Sound, Electrical, Kinetic, Potential, Nuclear and Chemical
What is special about energy?
Energy cannot be created or destroyed only changed from one source to another.
What does specific heat capacity men?
The specific heat capacity of a material tells us the energy required to raise the temperature of 1kg of that substance by 1 Degrees Celsius
What does latent heat mean?
Latent heat is the energy required to change the state of 1kg of a substance
There is no change in what when a substance changes what?
There is no change in TEMPERATURE when a substance changes STATE
What is known as the Kinetic theory?
The atomic model of a gas
What is pressure?
Pressure is the force per unit area
when volume decreases what happens to the pressure?
Pressure increases when volume decreases
When volume is halved what happens to the pressure?
Pressure doubles when volume is halved.
0 degrees Celsius is what in kelvin?
273 Kelvin