Exam Revision NCEA Level 3 Physics Exam Revision
Wednesday 25 September 2019
Monday 23 September 2019
Term 3 Week 10 2019
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 Inductance in D.C. Circuits
Ex 6I, p.308-310 Inductors Charge & Discharge
Ex 6J, p.311-312 Transformers
Ex 6K, p.314-315 A.C. Peak and r.m.s.
Ex 6L, p.316-317 A.C. Capacitor Reactance
Ex 6M, p.319-320 A.C. Inductor Reactance
Ex 6N, 321-324 A.C. RCL Impedance
RCL Phase Relationships
MIT Mathlet on RCL Phase Relationships - Interactive
Impedance of a Capacitor Resistor Circuit
Z = √(XC2 + R2)
θ = tan-1(-XC/R) = tan-1(-VC/VR)
The Capacitor Reactance is 90° behind the Resistance
The Capacitor Voltage is 90° behind the Resistor Voltage
Impedance of a Inductor Resistor Circuit
Z = √(XL2 + R2)
θ = tan-1(XL/R) = tan-1(VL/VR)
The Inductor Reactance is 90° ahead of the Resistance
The Inductor Voltage is 90° ahead of the Resistor Voltage
Impedance of a RCL Circuit
Z = √((XL - XC)2+ R2)
θ = tan-1((XL - XC)/R) = tan-1((VL - VC)/VR)
Resonance
A.C. Circuits & Resonance
MIT Physics Demo -- Resonant RLC Circuit
Monday 16 September 2019
Term 3 Week 7 2019
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 Inductance in D.C. Circuits
Ex 6I, p.308-310 Inductors Charge & Discharge
Ex 6J, p.311-312 Transformers
Vs/Vp = Ns/Np
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 Transformer
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
Faraday Cage
Tesla Coil & Faraday Cage
Tesla Coil & Faraday Cage
Exploding Cans with Electromagnets
Levitating with Electromagnets
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