Electricity Flashcards
Explain why the resistance of the filament lamp changes when the temperature increases
More ions collide with electrons therefore, inhibiting the flow of electrons and finally causing the wire to heat up
Advantages of lamps being wired in parallel circuits
- Each lamp can be controlled individually
- If one goes off, rest stay on
- They all get the same voltage
How do fuses protect circuits
If there is a surge of current higher than the fuse rating, the fuse wire melts and cuts off current completely which prevents the wire from overheating as well as leaving the appliance safe
Where can parallel circuits be used
- Living Room
- Basement
- Corridor
How is brightness affected when a lamp moves from a cold room to a hot room
As temperature increases, the current increases hence, the brightness increases
How is current and voltage distributed in parallel circuits
Voltage stays the same whereas current is conserved at each junction
Conversion from mA to A?
Divide by 1000
Is it true that when the temperature increases, the resistance of the thermistor also increases?
No because as the temperature increases, resistance decreases hence, current increases and voltage decreases
Why does the coil of wire heat up when there is a current in it?
The coil of wire has resistance where electrons collide with the ions and energy is transferred to the coil
Explain how another ink drop could be deflected in the opposite direction by a greater distance using the charged plates in the inkjet printer
The ink drop changes polarity therefore there is an increasing amount of charge on the plates
Definition of voltage?
Energy transferred per unit charge passed
How does voltage across a resistor connected in parallel compare with voltage across battery?
- Voltage is the same through both
- Because batter and resistor are connected in parallel
Explain how thermistor can be used to vary the current
- The resistance of the thermistor changes
- As temperature increases, the resistance decreases
- therefore, the current increases
Explain why the voltage across the LDR decreases when the resistance of the LDR decreases
- Larger current means larger voltage across the fixed resistor
- Total voltage remains constant
what is true for all series circuits?
- Current is the same everywhere
- Total voltage is shared
- Total resistance is the resistance of all resistors added together
