PHYSICS Electrical Circuits CHAPTER 4 (P4- The resistance of an appliance…
PHYSICS Electrical Circuits CHAPTER 4
P1- Some insulating materials become charged when rubbed together.
P3- Potential difference across a component= energy transferred ÷ charge.
P2- A battery consists of two or more cells connected together.
P1- Electrons are transferred when objects become charged... Insulating materials that become positively charged when rubbed lose electrons. Insulating materials that become negatively charged when rubbed together gain electrons.
P2- Every component has its own agreed symbol. A circuit diagram shows how components are connected together.
P1- Like charges repel. Unlike charges attract.
P3- Resistance= potential difference ÷ current
P1- The force between two charged objects is a non-contact force.
P2- The size of an electrical current is the rate of flow of charge.
P2- The equation for the electrical current of a circuit is CURRENT= CHARGE FLOW ÷ TIME TAKEN
coulombs amps seconds
P3- Ohm's law states that the current through a resistor at constant temperature is directly proportional to the potential difference across the resistor.
P3- Reversing the potential difference across a resistor reverses the current through it.
P4- The resistance of an appliance is.. RESISTANCE (ohms)= POTENTIAL DIFFERENCE (volts) ÷ CURRENT (amps).
P4- A thermistor's resistance decreases if its temperature increases.
P4- A filament lamp's resistance increases if the filament's temperature increases.
P4- Diode : Forward resistance low: reverse resistance high
P4- An LDR's resistance decreases if the light intensity on it increases.
P5- For components in series: the current is the same in each component. The total potential difference is shared between the components. Adding their resistance gives the total resistance.
P5- For cells in series, acting in the same direction, the total potential difference is the sum of their individual potential differences.
P5- Total resistance= R1 + R2
P5- Adding more resistors in series increases the total resistance because the current through the resistors is reduced and the total potential difference across them is uncharged.
P6- For components in parallel: The total current is the sum of the currents through the separate components. The potential difference across each component is the same.
P6- The bigger the resistance of a component, the smaller the current that will pass through that component.
P6- The current through a resistor in a parallel circuit is CURRENT (amps)= POTENTIAL DIFFERENCE (volts) ÷ COMPONENT RESISTANCE (ohms)
P6- Adding more resistors in parallel decreases the total resistance because the total current through the resistors is increased and the total potential difference across them is unchanged.
ELECTRICAL CHARGES AND FIELDS
CURRENT AND CHARGE
POTENTIAL DIFFERENCE AND RESISTANCE