2654002
Description
Flashcards by Gretta Mildred, updated more than 1 year ago
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Created by Gretta Mildred
almost 9 years ago
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| Question | Answer |
| What is this? | The cell |
| What is this? | An open switch |
| What is this? | A closed switch |
| What is this? | A lamp/ filament lamp |
| What is this? | A battery |
| What is this? | A voltmeter |
| what is this? | Resistor |
| What is this? | Fuse |
| What is this? | An ammeter |
| What is this? | A variable resitor |
| What is this? | Thermistor |
| What is this? | Light-dependent resistor |
| What is this? | Light emitting diode |
| What is this? | A diode |
| What has to be put in series? | An ammeter |
| What has to be connected in parallel? | A voltmeter |
| Resistors and current | The current through a resistor is directly proportional to potential difference. Different resistors have different resistances |
| Filament lamp in relation to resistance? | As the temperature of the filament increases, the resistance increases, hence the curved graph. |
| Diode and resistance | Current will only flow through a diode in one direction. The diode has very high resistance in the opposite direction |
| 1. Why does resistance increase with temperature? | 1. When an electrical charge flows through a resistor, some of the electrical energy is transferred to heat energy- resistor gets hot |
| 2. Why does resistance increase with temperature? | This heat energy causes the ions in the conductor to vibrate more |
| 3.Why does resistance increase with temperature? | This makes it more difficult for the charge-carrying electrons to get through the resistor- the current can't flow as easily- resistance increases |
| 4.Why does resistance increase with temperature? | For most resistors, there is a limit to the amount of current that can flow. More current means an increase in temperature, which means an increase in resistance, which means the current decreases again |
| What is a diode used for? | Made of semiconductor material e.g. silicon. Regulates the potential difference in circuits |
| What is a light-emitting diode used for? | LEDs emit light when a current flows through it in the FORWARD direction. Use smaller current. Indicate presence of current in a circuit. |
| What are light- dependent resistors used for? | They are dependent on the intensity of light. Bright light= resistance falls, darkness= high resistance |
| What is a thermistor? | Temperature-dependent resistor. HOT conditions= resistance DROPS, COOL conditions = resistance INCREASES |
| In series circuits, potential difference is..? | SHARED |
| In series circuits, current is.. | THE SAME EVERYWHERE |
| In series circuits, resistance..? | ADDS UP |
| In series circuits, cell voltages..? | ADD UP |
| In parallel circuits, potential difference is..? | THE SAME ACROSS ALL COMPONENTS |
| In parallel circuits, the current is...? | SHARED- total current flowing is equal to the total of all the currents through the separate components |
| What is the voltage of UK mains supply? | 230 volts |
| What is the UK mains supply- alternating or direct current? | Alternating current- 50Hz |
| What is AC? | Alternating current- current constantly changes direction |
| What is DC? | DC- used by cells and batteries, current always flows in THE SAME DIRECTION |
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