Wednesday 14 October 2020

Term 4 Week 1 2020

 External Exam Revision

Learn Coach Level 3 Physics Link


Learn Coach Waves

NCEA Physics L3 Waves: Introduction


NCEA Physics L3 Waves: Standing waves


NCEA Physics L3 Waves: Standing wave harmonics




Learn Coach Mechanics

NCEA Physics Level 3 Mechanics: Translational Motion - Part 1


NCEA Physics Level 3 Mechanics: Translational Motion - Part 2


NCEA Physics Level 3 Mechanics: Circular Motion - Part 1




Learn Coach Elelctricity

NCEA Physics Level 3 Electricity: DC circuits


NCEA Physics Level 3 Electricity: Capacitors - Part 1



NCEA Physics Level 3 Electricity: Capacitors - Part 2



Monday 24 August 2020

Term 3 Week 6 2020

 Homework

  • Ex 6A, p.251-254 Level 2 D.C. Circuit Revision
  • Ex 6B, p.261-261 Internal Resistance of a Battery
  • Ex 6C, p.267-272 Kirchhoff's Laws
  • Ex 6D, p.277-280 Capacitors Ep = ½ QV
  • Ex 6E, p.283-284 Capacitors C = 𝜺r𝜺oA/d
  • Ex 6F, p.289-292 Capacitor Networks (Series & Parallel)
  • Ex 6G, p.298-300 Capacitor Charge & Discharge
  • Ex 6H, p.303-305 Faraday's Law, 𝜺 = - Δ𝛟/Δt

  • Right Hand Screw Rule


    Right Hand Slap Rule

    Magnetic Flux










    Lenz's Law

    Faraday's Law & Lenz's Law


    Inductance






    Transformers


    The ratio of the secondary to primary voltage is equal to the ratio of the secondary to primary turns

    Vs/Vp = Ns/Np

    In an Ideal Transforme
    Secondary Power = Primary Power
    In reality, energy is lost through heat from eddy currents generated in the soft iron core from the changing flux.

    NB: As Voltage is often referred to as e.m.f. the Symbol "e" or "E" is often used in engineering to refer to e.m.f.
    This is the case in the video below.
    After explaining how basic Transformers work, this video goes on to explain 3-Phase Transformers.

    NZ Street Step-Down Transformer

    Internal Diagram of a Transformer

    Monday 3 August 2020

    Term 3 Week 3 2020

    Homework
  • Ex 6A, p.251-254 Level 2 D.C. Circuit Revision
  • Ex 6B, p.261-261 Internal Resistance of a Battery
  • Ex 6C, p.267-272 Kirchhoff's Laws
  • Ex 6D, p.277-280 Capacitors Ep = ½ QV
  • Ex 6E, p.283-284 Capacitors C = 𝜺r𝜺oA/d
  • Ex 6F, p.289-292 Capacitor Networks (Series & Parallel)
  • Ex 6G, p.298-300 Capacitor Charge & Discharge

  • Capacitor
    C = Q/V


    Capacitors
    Basic Definition
    Physical Parameters
    Energy Stored
    Ep = ½ QV


    Capacitors & Capacitance

    Capacitors Explained

    Dielectric

    An insulating material placed in between the capacitor plates to increase the Capacitance

    C = 𝜺r𝜺oA/d






    Dielectrics in Capacitors

    PhET Capacitor Lab Basics - App


    Capacitor Circuits


    Capacitors in Series
    Calculating Voltage Charge and Total Capacitance

    Capacitors in Parallel
    Calculating Voltage Charge and Total Capacitance


    Capacitors in Parallel vs Capacitors in Series


    Capacitors in Combination
    Series & Parallel Capacitors

    Capacitors in Combination
    Patrallel & Series Capacitors

    Capacitors in Series
    Calculating Voltage Drop


    Capacitors in Series
    Calculating the Charge Stored

    Capacitors in Series
    Calculating the Equivalent Capacitance


    Capacitors in Parallel
    Calculating Voltage Drop

    Capacitors in Parallel
    Calculating the Charge Stored


    Capacitors in Parallel
    Calculating the Equivalent Capacitance


    Capacitor Charge & Discharge



    RC Circuits 1: Charging and Discharging a Capacitor


    Thursday 30 July 2020

    Term 3 Week 2 2020

    Homework
  • Ex 6A, p.251-254 Level 2 D.C. Circuit Revision
  • Ex 6B, p.261-261 Internal Resistance of a Battery
  • Ex 6C, p.267-272 Kirchhoff's Laws

  • Electrical Charge

    Current
    Current is the rate of flow of Charge

    I = Δq/Δt

    Current

    Voltage
    Voltage (Potential Difference) is the change in energy (work done) to each coulomb of charge between two points on a circuit, or two points across an electric field

    Voltage
    Voltage (Potential Difference) is the change in energy (work done) to each coulomb of charge between two points on a circuit, or two points across an electric field

    V = ΔE/Q

    Ohm's Law & Resistance

    Power


    Circuit Symbols

    Ohm's Law



    Ohm's Law


    Internal Resistance of a Battery
    Batteries can be thought of as having an ideal voltage supply E.M.F. (Electromotive Force) in series with an internal resistance

    V = 𝛆 - Ir


    How to find the internal resistance of a battery

    Kichhoff's Laws
    Kirchhoff’s Current Law
    At any junction in a circuit, the total current entering the junction equals the total current leaving the junction
    Kirchhoff’s Voltage Law
    Around any closed path of a circuit, the total of all the potential differences, V, is zero

    Kirchhoff's Rules for Circuit Analysis - Explanation

    Kirchhoff's Rules for Circuit Analysis - Example 1

    Kirchhoff's Rules for Circuit Analysis - Example 2

    Kirchhoff's Rules for Circuit Analysis - Example 3