physics
GCSE
GCSE
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Lernkarten
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
