# Physics Unit 1 AS AQA A Equations

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• Created by: Bryony
• Created on: 14-12-14 15:54
Specific charge (C/kg^2)
charge(C)/mass (kg)
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Energy of one photon (Joules)
hf (Planck's constant = 6.63x10^-34)x(frequency of light in Hz)
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Energy of one photon (Joules)
hc/λ (Planck's constant = 6.63x10^34)x(speed of light in a vacuum = 3x10^8)/(wavelength)
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Minimum energy needed for pair production
E˅min = 2E˅0 (minimum energy needed = 2 x rest energy of particle type produced in MeV)
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Minimum energy of a photon produced by annihilation
E˅min = E˅0 (minimum energy of photon produced = rest energy of particle type annihilated in MeV)
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Neutron decay
Neutron → proton + electron + antineutrino
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Beta plus decay
Proton → neutron + positron + neutrino
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Threshold frequency (f˅0)
φ/h (work function/6.63x10^-34)
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Photoelectric equation
hf = φ + E˅k (Planck's constant x frequency = work function + maximum kinetic energy)
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Maximum kinetic energy a photoelectron can have
1/2mv˅max^2 (1/2 mass x maximum velocity^2)
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Convert between eV and J
1eV = 1.6x10^-19J
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de Broglie wavelength
λ = h/mv (de Broglie wavelength = Planck's constant/mass x velocity)
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Charge
ΔQ = IΔt (Charge(C) = current(A) x time)
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Potential difference
V= W/Q (p.d.(V) = work done (J)/charge (C))
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Convert between V and JC^-1
1V = 1JC^-1
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Resistance
R = V/I (resistance (ohms) = p.d./current)
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Ohmic conductors
I α V (Current is directly proportional to p.d.)
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Resistivity
ρ = RA/L (resistivity = (resistance x cross-sectional area)/length)
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Power (W)
P = E/t (Power = energy/time)
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Power (W)
P = VI (Power = p.d. x current)
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Potential difference (V)
V = IR (p.d. = current x resistance)
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Power (W)
P = V^2/R (power = p.d.^2 / resistance)
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Power (W)
P = I^2 x R (Power = current^2 x resistance)
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Energy (J)
E = VIt (p.d. x current x time)
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Energy (J)
E = (V^2/R)t ((p.d.^2/resistance) x time)
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Energy (J)
E = I^2Rt (current^2 x resistance x time)
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E.M.F.
ε = E/Q (electromotive force = electrical energy/charge)
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Electromotive force
ε = I(R+r) (e.m.f. = current x (load resistance + internal resistance)
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e.m.f.
ε = V+v (e.m.f = terminal p.d. + lost volts)
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Terminal p.d.
V = ε - v (terminal p.d. = e.m.f. - lost volts)
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Terminal p.d.
V = ε - Ir (terminal p.d. = e.m.f. - (current x internal resistance)
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Kirchhoff's 2nd law
ε = ΣIR
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e.m.f. in series circuits
ε = V1 + V2 + V3
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Resistance in series circuits
R˅total = R1 + R2 + R3
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Current in parallel circuits
I = I1 + I2 + I3
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V/R˅total
(V/R1) + (V/R2) + (V/R3)
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1/R˅total
(1/R1) + (1/R2) + (1/R3)
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E.M.F. for cells in series
ε˅total = ε1 + ε2 + ε3
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Potential divider
V˅out = (R2/(R1 + R2))V˅s
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Analysing oscilloscopes
f = 1/t (frequency = 1/time)
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## Other cards in this set

### Card 2

#### Front

hf (Planck's constant = 6.63x10^-34)x(frequency of light in Hz)

#### Back

Energy of one photon (Joules)

### Card 3

#### Front

hc/λ (Planck's constant = 6.63x10^34)x(speed of light in a vacuum = 3x10^8)/(wavelength)

### Card 4

#### Front

E˅min = 2E˅0 (minimum energy needed = 2 x rest energy of particle type produced in MeV)

### Card 5

#### Front

E˅min = E˅0 (minimum energy of photon produced = rest energy of particle type annihilated in MeV)