| What is the symbol for an ohmic conductor | ohmic conductor |
| What is the symbol for a semiconductor diode | semiconductor |
| What is the symbol for a fileament lamp | circle with cross |
| Why when the resistance is fixed is current and pd across a component directly proportional | Because V=IR
So if R doesnt change and
the current does then the voltage must also, and visa versa |
| If the resistance is fixed along a wire, what is the relationship between the current and the pd across it if the pd was to change | Directly proportional to one another |
| How would you define an ohmic conductor | A resistor that follows ohms law |
| What is ohms law? | V=IR |
| What is a semiconductor diode | A diode (lamp) that only allows the flow of electricity in one direction |
| Whats the current voltage characteristic for a filament lamp | s |
| Whats the current voltage characteristic for a ohmic conductor | s |
| Whats the current voltage characteristic for a semiconductor diode | Fine to exclude the negative current |
| Why does an ohmic conductor have the shaped graph it has? | WRONG: //Because when current is increased the frequency of collisions with electrons with the ions in the lattice increases
This make the ions vibrate more, increasing temperature
Increase in temperature makes collisions even more likely, increasing resistance//
RIGHT:
Because ohms law
V = IR
This rearanges to V/I = R (which is a constant)
So V/I is directly proportional |
| Explain why diode only allows charge to flow in one direction | Cause it has a very high resistance one way and a very low resistance the other way |
| Explain why for a semiconducting diode after a lot of negative pd does current all of a sudden shoot down | Diodes broken down, so the current becomes infinite, and a short circuit. |
| Explain why a filement lamp has the IV characteristics it does | As the potential difference across a filament lamp increases,
the current increases
and the energy dissipated, as heat, increases, resulting in a higher temperature.
As the temperature increases, resistance of the filament increases.
The collision between the free electrons and the lattice ions increases due to more rigorous vibration of the lattice ions |
