Physics

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  • Physics
    • Imaging
      • Pixels
        • Resolution= Distance / No. of Pixels
      • Digital
        • 1 bit  - Smallest amount of information (0 or 1)
          • 1 byte = 8 bits
          • If 'I' is the number of bits
            • 2^I is the number of alternatives
          • To find number of bits log2(No. of choices needed)
        • Uses Binary
        • No. of Alternatives = 2
      • No. of bits per image
        • No. of pixels x No. of bits needed for colour scheme
          • No. of bytes = No. of bits / 8
      • Coloured Images
        • Red + Green
          • Yellow
        • Red + Blue
          • Purple
        • Blue + Green
          • Syan (Turquoise)
        • Red + Blue + Green
          • White
      • Finding Edges
        • Laplace Kernel
          • 4
            • 0
            • -1
            • 0
            • 0
            • 0
            • -1
            • -1
            • -1
          • Negative values become 0
      • Smoothing
        • Median - replace with median of surrounding values
        • Mean - Replace with mean of surrounding squares
    • Testing Materials
      • Young's Modulus
        • Stress (Nm-1) = Force (N) / Area (m2)
        • YM (Pa) = Stress (Pa) / Strain
        • Strain = Extension (m) / Orig. Length (m)
      • Types of materials
        • Ceramic
          • Electrical Insulator
            • Plastic
              • Often Malleable
              • Can be tough
              • Can be hard
              • Ductile
          • Brittle
            • Readily cracks on impact or shock
          • Thermal Insulator
            • Plastic
              • Often Malleable
              • Can be tough
              • Can be hard
              • Ductile
          • Hard
        • Metals
          • Tough
            • Can withstand large shocks or impacts before breaking
          • Sonorous
          • Hard
            • Does not easily scratch
          • Electrical Conductor
          • Strong
            • Can withstand high stress before yield or fracture
          • Thermal conductor
          • Malleable
            • Can be hammered into sheets
          • Ductile
            • Can be drawn out into a wire
      • Resistance = Resistivity x Length / Area
      • Hooke's Law
        • Stretching Force (N) =Spring Constant (Nm-1) x Extension (m)
        • Only applies up to the elastic limit
      • Conductance = Conductivity x Area / Length
    • Signalling
      • Digital
        • 1 bit  - Smallest amount of information (0 or 1)
          • 1 byte = 8 bits
          • If 'I' is the number of bits
            • 2^I is the number of alternatives
          • To find number of bits log2(No. of choices needed)
        • Uses Binary
        • No. of Alternatives = 2
      • Sampling Frequency
        • At every sampling frequency round to nearest value
          • Convert each point sampled on curve to binary
            • Draw in bursts digital on/off graph
        • Sampling Frequency must be at least 2x highest frequency
        • Highest Frequency - W (Hz)=1/T(s)
      • Digitizing a Signal
        • At every sampling frequency round to nearest value
          • Convert each point sampled on curve to binary
            • Draw in bursts digital on/off graph
      • No. of levels needed
        • V-Signal (V) / V-Noise (V)
        • No. of bits = log2(No. of levels)
      • Velocity = Frequency x Wavelength
      • Transmission Rate
        • Sampling Frequency x No. of Bits
        • 2W log2 ( V-signal / V-noise)
          • Sampling Frequency x No. of Bits
      • Transmitting Waves
        • Digital
          • Amplitude Modulated or Frequency Modulated
        • Analogue
          • Amplitude Modulated
      • Wave View
        • Amplitude same
          • Frequency View
            • Frequency on x-axis
        • Frequency = 1/T
      • Frequency View
        • Frequency on x-axis
      • Polarisation
    • Looking Inside Materials
      • Internal Structure
        • Crystalline rows of ions in a strict order
        • Polycrystalline - A structure made up of many interlocking crystals with grain boundaries.
        • Amorphous - Random atoms and molecules in no order
      • Bonding in materials
        • Metallic - non directional
        • Ionic - Non directional
        • Covalent - Directional
      • Alloys
        • Impurities pin dislocatioons so they cannot move through the whole crystal.
      • Metals
        • Sea of electrons allows positive ions to just slip past each other
          • Ductile
            • Can be drawn out into a wire
    • Sensing
      • Types of Resistor
        • Resistance increases with voltage as temperature increases
          • Resistance calculated by taking spot values
        • Ohmic Resistor
          • Ratio of V/I is a constant
            • Resistance is the constant
      • Resistors
        • Series
          • Rt = R1+R2
          • I1=I2=I3
          • Vt=V1+V2
        • Parallel
          • 1/Rt = 1/R1 +1/R2
          • Rt = R1R2/R1+R2
          • Iseries = Ipara1+ Ipara2
          • V=V of battery
      • Semiconductors
        • LDR, Diode, Thermistor
          • In a potential divider circuit
            • V of LDR/ V of Ohmic Resistor = R of LDR/R of Ohmic Resistor
            • Sensing Circuit
              • Sensitivity = Change in Output/Change in Input
                • For LDR: Change in PD/Change in distance
                • Gradient
              • Resolution
                • Smallest detectable change in input
                • Precision / Sensitivity
              • Sensing
                • Types of Resistor
                  • Resistance increases with voltage as temperature increases
                    • Resistance calculated by taking spot values
                  • Ohmic Resistor
                    • Ratio of V/I is a constant
                      • Resistance is the constant
                • Resistors
                  • Series
                    • Rt = R1+R2
                    • I1=I2=I3
                    • Vt=V1+V2
                  • Parallel
                    • 1/Rt = 1/R1 +1/R2
                    • Rt = R1R2/R1+R2
                    • Iseries = Ipara1+ Ipara2
                    • V=V of battery
                • Semiconductors
                  • LDR, Diode, Thermistor
                    • In a potential divider circuit
                      • V of LDR/ V of Ohmic Resistor = R of LDR/R of Ohmic Resistor
                      • Sensing Circuit
                        • Sensitivity = Change in Output/Change in Input
                          • For LDR: Change in PD/Change in distance
                          • Gradient
                        • Resolution
                          • Smallest detectable change in input
                          • Precision / Sensitivity
                  • Diodes have forward and reverse bias, current can only flow one way
                • Potential Divider
                  • V1/V2 = R1/R2
                • EMF and internal resistance
                  • E=V+Ir
                • Improving a circuit
                  • 2 semiconductor sensors cancels out effect of other factors
                • Equations
                  • I=Q/t
                    • V=W/Q
                      • W=ItV
                        • R=V/I
                          • R=pL/A
                            • P=W/t
                              • P=IV
                                • E=Pt
        • Diodes have forward and reverse bias, current can only flow one way
      • Potential Divider
        • V1/V2 = R1/R2
      • EMF and internal resistance
        • E=V+Ir
      • Improving a circuit
        • 2 semiconductor sensors cancels out effect of other factors
      • Equations
        • I=Q/t
          • V=W/Q
            • W=ItV
              • R=V/I
                • R=pL/A
                  • P=W/t
                    • P=IV
                      • E=Pt

Comments

tahrifkhan


very helpfull cheers

Mrs Jones

If your doing AQA AS physics this is for you.  It will give you the big picture of the course.  I'd print (I can read on a colour A4) it off  and keep it at the front of your file.  That way you can tick off what you've covered as a check you've got the basics and know what's coming next.  Having taught this syllabus I found the titles for each section not overly informative e.g Sensing is where you'll cover d.c electricity?    As you can see the content of each section you could add additional titles to add clarity. 

superrabi

GOOD reminder for OCR B: really needed!!!

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