GCSE


Kartei Details

Karten 32
Sprache English
Kategorie Naturkunde
Stufe Mittelschule
Erstellt / Aktualisiert 01.06.2016 / 01.06.2016
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Charge

• Charge = Current x time (Q=It)

Voltage

• Voltage = Current x Resistance (V=IR - also known as Ohms Law)

Circuit types

parallel and series

Circuit Current, Voltage and Resistance rules

o Series - Current same, voltage shared, add resistance to get total resistance o Parallel - Voltage same current shared in branches of circuit

Light bulb

• Light bulb - effects of heat on resistance (non-ohmic graph of V against I is not straight line)

Special resistors

- LDR, thermistor and diode ,Graph shapes and uses

  • Alternating and Direct Current 

o Graphs of wave forms and sources

  • Domestic Electricity Supply

o Plugs and wiring (Blue Neutral, Brown Live, Green and Yellow Earth) ♣ Common Faults o Protection by Earth wire, fuses and double insulation

Electrical Power

• Electrical Power = Current x Voltage (P=IV but also using V=IR, P=I2R and P= V2/R)

Electrical Energy

• Electrical Energy = Current x Voltage x Time (E=IVt)

Weight

• Weight = mass x gravity (W=mg)

  • Resultant Forces 

o All forces in same plane (ie: horizontal) can be added together to give an equivalent single force

Newton's 2nd Law 

• Newton's 2nd Law Force = mass x acceleration (F=ma)

  • Friction and Drag and their effects

slow things down

  • Terminal Velocity - sky diver

o Forces balanced , Acceleration zero , Constant speed

  • Stopping distances

o Factors affecting thinking (drugs and drinking) and braking (road conditions and condition of car) distances

Work Done

• Work Done = Force x distance (W=Fd) , Work also equals change in energy

Power 

Power = rate of doing Work (P=W/t)

Kinetic Energy 

• Kinetic Energy = ½ mass x speed squared (KE= ½ mv2)

Gravitational Potential Energy 

• Gravitational Potential Energy = mass x gravity x height gained (GPE = mgh)

  • Conservation of energy in falling objects

o GPE at start = KE at end

Types of graph for metal wire

• Types of graph for metal wire, spring and rubber (hysteresis)

  • Hooke's Law (force directly proportional to extension)

o Force = spring constant x extension (F=kx)

Combinations of springs 

• Combinations of springs - series and parallel

Ray diagrams drawn correctly 

o Arrow on rays , Normal - (90o to surface) , Identification of angles of incidence, reflection and refraction

  • Reflection from plane (flat) mirrors 

o Position of image (equal distance behind mirror as in front) and laterally inverted o Law of Reflection ♣ Angle of Incidence = Angle of Reflection o Reflection from concave and convex mirrors and their uses

  • Refraction

o Light ray diagrams of rays passing from air to water or glass and from water or glass to air

  • Refractive Index

o Refractive Index = Sine Angle of Incidence OR n = Sin i Sine Angle of Refraction Sin r

Total Internal Reflection and Critical Angle

o Sine Critical Angle = 1/Refractive Index (Sin c = 1/n) o Only when ray travels from more dense to less dense mediums o Uses - endoscopes, optical fibres (diagram) o Turning prisms

  • Absolute Zero and Kelvin Scale of temperature

o 0K = -273oC ♣ Conversion from one scale to the other o Kelvin scale is proportional to the mean (average) kinetic energy of gas particles o Energy of particles at absolute zero is zero

  • Pressure in a gas 

o Collisions of particles with walls of containers o Each collision exerts a force o Average of total force on each wall of container the same ♣ All surfaces see same pressure as P=F/A

  • Boyles Law for gases

o p1V1 = p2V2 ♣ Constant mass of gas ♣ Constant temperature ♣ Examples - breathing and aerosols