An important skill in physics is to rearrange formulas. Click the picture to watch the lesson movie.
Changing the subject!⤴
from Mr Mallon @ Helpmyphysics
Tag Archives: Standard Grade
Helpmyphysics 2023-10-30 20:52:03⤴
from Mr Mallon @ Helpmyphysics
The period of a satellite is the time it takes for one complete orbit.
Click the picture to see two satellites orbiting the Earth. Which one has the biggest period.
Determine the periods of each satellite.
AC and DC on an Oscilloscope Screen⤴
from Mr Mallon @ Helpmyphysics
For Higher Physics students:
- Determine the period and frequency of the ac supply
- Find the rms voltage of the ac signal
Combine those resistors!⤴
from Mr Mallon @ Helpmyphysics
Use this sim to find out about the resistance of combined resistors.
The Hunt for Exoplanets⤴
from Mr Mallon @ Helpmyphysics
Click the above picture for information on how astronomers detect exoplanets.
Exoplanets are planets orbiting a star outside our solar system.
Helpmyphysics 2023-02-19 16:12:58⤴
from Mr Mallon @ Helpmyphysics
Click on the picture to help fill in your summary sheet on voltage divider sensors.
Charge that capacitor!⤴
from Mr Mallon @ Helpmyphysics
A capacitor can be used in a sensor circuit to switch on a transistor after a time interval.
Such a voltage divider circuit will act as a kind of timer.
The time the voltage across the capacitor reaches 0.7 v, to switch on the transistor, can be short or long depending on the size of the capacitance of the capacitor or the size of the resistor its being charged through.
To lengthen the time interval the resistance can be made bigger or the vakue of the capacitor’s capacitance can be made bigger.
Ohm’s Law Sim⤴
from Mr Mallon @ Helpmyphysics
Use this sim to determine the relationship between the voltage across a resistor and the current passing through it.
Notice the variable resistor will vary the current in the circuit.
Take current and voltage readings in a table and plot a graph current in the x-axis and voltage in the y-axis.
Cool down with a thermistor!⤴
from Mr Mallon @ Helpmyphysics
A thermistor is a resistor whose resistance changes with temperature.
When it becomes cold its resistance gets bigger. When it becomes hot its resistance becomes smaller.
Check the voltages across the voltage divider.
The mosfet acts like a switch. When the voltage at its gate becomes bigger than 2 volts it will switch on the relay which in turn switches the fan on.
Share the voltage!⤴
from Mr Mallon @ Helpmyphysics
Click the picture to go to the sim.
Some questions:
- What do you notice about the variable resistor’s voltage as its resistance increases?
- What do you notice about the sum of the voltages across the resistors?
- For each resistor in turn, take the ratio of voltage across it and divide by the resistance. What do you notice?