Physics

• In a series circuit, the total resistance is equal to the sum of the resistances of each individual component.
• • Ammeter: A device that measures the current in the loop of the circuit that it is connected in series with. An ideal ammeter is modeled to have zero resistance.
• • Current: The rate of flow of charge in a circuit.
• • Electromotive Force: The amount of energy transferred by a source, to each unit of charge that passes through it.
• Charge flow (Q) is equal to the product of current (I) and the time taken (t)
• A battery consists of two or more cells connected together.

  The size of an electric current is the rate of flow of charge.

  The equation for the electric current of a circuit is I=Q/t.
• The size of an electric current is the rate of flow of electric charge.
• The bigger the number of electrons that pass through a component each second, the bigger is the current passing through it.
• The voltmeter measures the potential difference across the component.
• 1. The unit of potential difference is Volts (V) and the unit of current is Amps (A)
• If we connect several resistors in parallel with a power supply, the total resistance will be less than any single resistor because the current splits between them.
• When components are connected in parallel, they have separate paths for the current to travel along
• In parallel circuits, the current can split up into different branches so some components may receive more current than others
• A diode is a non-ohmic conductor, meaning it has a resistance that is different at different temperatures
• Thermal energy: Energy transferred by heating or cooling a substance.
• Temperature: The average kinetic energy of the particles in a substance.
• Thermal energy is measured in joules or J.
• Temperature is to do with how hot or cold something is. It is measured in degrees Celsius.
• Independent Variable: what we change
• Dependent variable: what we measure
• Control variable: what we keep the same
• Kinetic energy is equal to half times mass times velocity squared and is measured in joules, with mass measured in kilograms and velocity measured in meters per second.
• The equation for kinetic energy is KE = 1/2 x m x v^2
• Gravitational Potential Energy (GPE) is when objects are lifted against gravity. GPE increases as the object rises and decreases as the object falls.
• Potential Energy is stored energy due to an object's position relative to another object or its height above ground level. The higher up it is, the more potential energy it has.
• Power is the rate at which work is being done. Power is calculated using the equation P=W/t where P is power, W is work done and t is time taken.
• Acceleration and force are both vector. They have magnitude and direction.
• Average speed is the total distance travelled divided by the total time taken.
• Velocity is the speed of an object moving in a particular direction. Velocity is a vector quantity with magnitude and direction.
• The formula for calculating average velocity is vavg = displacement / time
• How are electric circuits shown in diagrams? An electrical circuit is drawn by using a solid line for the wires. Symbols are drawn on the path of the wire to represent different components
• The difference between battery and a cell: A cell is a single unit of device that converts chemical energy into electrical energy. A battery is a collection of cells that converts chemical energy into electrical energy.
• Electrical current depends on resistance and potential difference.
• An electric current is a flow of charged particles.
• Charge is measured in coulombs, C.
• Current I = Quantity of charge Q/ time taken t

  I = Q/t
• Potential difference: the difference in potential between two points that represents the work involved or the energy released in the transfer of a unit quantity of electricity from one point to the other.
• (Ω) The unit of the electrical resistance, measured with direct current, is the ohm
• ohms law

  
• Power = Voltage x Current