Edexcel IGCSE Physics

• Frequency is....

  the total number of waves per second.
• Amplitude is measured from....

  the middle to the peak. (NOT FROM TROUGH TO PEAK)
• Wavelength is....

  the distance from a point on one wave to the same point on the next wave. (Easiest to measure it from the peak of one to the peak of the next)
• Draw and label a Longitudinal wave.

  Give and example.

  example: sound wave

  
• Draw and label a Transverse wave.

  Give an example.


  example: light wave

  
• 2 types of waves....

  transverse and longitudinal
• Waves transfer....

  Waves do not transfer....

  ..... energy and information

  ..... matter
• What does it mean to induce a charge? For example, when a charge balloon is placed near a wall, or when a lightning cloud is near a lightning rod.

  Induction of charge is when the charge of one object causes another object to become the opposite charge due to attraction or repulsion.

  
• What are the potential dangers of electrostatic charges?

  (Paper 2 Only)

  Electric charge can discharge and cause a spark that could ignite a fuel causing a fire or explosion.

  Sparks can damage electrical equipment.
• Like charges _____ and opposite charges ______

  (Paper 2 Only)

  1. repel

  2. attract
• Voltage =


  Energy Transferred / Charge

  V = E / Q
• Voltage is...

  the energy transferred per unit of charge.
• A bulb is connected in series with a bulb that has twice the resistance. How will the voltage across each bulb compare?


  The bulb with more resistance will take more energy so there will be a larger voltage across the second bulb. If the resistance is double then is will take double the voltage.

  For example, if 6V is available, the first bulb will take 2V and the second bulb will take 4V.
• Current is conserved at a junction.

  What does this mean?

  The current into a point is equal to the current out of a point. This is because charge cannot be lost in the circuit.

  
• Current (Amps) =

  Charge (Coulombs) / Time (seconds)

  I = Q / t
• Draw the Current-Voltage graphs for a fixed resistor, a filament lamp, and a diode.

  Describe how to investigate these experimentally.

  - Place the component of interest in a series circuit with a power supply and a variable resistor.

  - Place an ammeter in series with the component, and a voltmeter across the component.

  - Use the variable resistor to vary the current in the circuit.

  - Record the voltage for a range of current values.

  - Plot a graph of Current against Voltage

  
• How does the current in a series circuit depend on the voltage supplied?

  In general, increasing voltage increases the current.
• A Parallel Circuit....


  - Has more than one pathway for current

  - The Current splits down different paths

  - The Voltage is the same across every path

  - If one part of the circuit, other parts of the circuit can keep working
• A Series Circuit....


  - Has one loop

  - The current is same all the way around

  - The voltage is shared between components

  - If one part breaks, the whole circuit stops working
• Conventional Current is....

  The rate of flow of positive charge from positive to negative.
• Current is a flow of....

  Negatively charged electrons
• Ohm's Law: Voltage =


  Current x Resistance

  V = I x R
• Ohm's Law says....

  Current is proportional to voltage (not true for all components).
• Draw the symbol for an open and a closed switch.

  What does it do?

  Allows current to flow when closed, and stops current when open.

  
• Draw the symbol for a cell.

  What does it do?

  Provides a voltage to the circuit.

  
• Draw the symbol for a filament bulb.

  What does it do?

  Emits Light.

  Indicates that a current is flowing.

  
• Draw the symbol of a Light Emitting Diode (LED).

  What does it do?

  Allows current to flow in one direction only. Indicates a current is flowing.

  
• Draw the symbol of a Diode.

  What does it do?

  Allows current to flow in one direction only.

  
• Draw the symbol of a Variable Resistor.

  What does it do?

  Controls the current in a circuit by altering the resistance in the circuit. Higher Resistance, lower current.

  Lower Resistance, higher current.

  
• Draw the symbol of an LDR.

  How does light intensity affect the resistance of a Light-Dependent Resistor (LDR)? (How does this change in resistance affect the current through the LDR?)

  Brightness Increase Resistance Decrease - Current Up (and the opposite way round too)

  
• What does a Voltmeter do?

  Draw a circuit showing where you would add a Voltmeter


  A Voltmeter measures Voltage. A Voltmeter is always connected in parallel (or across the component).

  
• What does an Ammeter do?

  Draw a circuit showing where you would add an Ammeter


  An Ammeter measures Current. An Ammeter is always connected in series (or in line with the component).

  
• Draw the symbol of a thermistor.

  How does temperature affect the resistance of a Thermistor? (How does this change of resistance affect the current through the Thermistor?)

  Temperature Up Resistance Down - Current Up (and the opposite way round too)

  
• What does a resistor do?

  Draw the symbol for a resistor

  It reduces the current due to collisions between electrons and lattice ions in the resistor, causing a transfer of energy and an increase in temperature.

  
• A Static charge can be built up on an insulator by....

  (Paper 2 only)

  Friction between two objects causing electrons to transfer from one material to the other, leaving one material with a negative charge (gained electrons), and the other with a positive charge (lost electrons).
• Uses of static electricity include....

  (Paper 2 only)

  Ink jet printers, photocopiers and spray paint
• What particles are found in the nucleus of an atom?

  protons and neutrons
• What is an Electrical Insulator and give an example? (Paper 2 only)

  Do not allow a current to flow.

  Rubber, glass and plastics are examples.
• What is an Electrical Conductor and give an example? (Paper 2 only)


  A material that allows a current to flow.

  Metals (e.g. Copper, Aluminium, Gold, etc.)
• What is D.C.?

  Direct Current where the flow is in one direction only (battery)