Equations
Equation sheet, and the ones to memorise
Every equation used across the notes, grouped by unit and linked back to the lesson it came from. Each is marked according to whether it is printed on the AQA data sheet or is one you have to carry in your head.
The 22 to 25 you have to know by heartNot on the AQA data sheet: 21 core, plus your one option34 equations
21 of these are core, and everybody sits them. The other 13 sit in the five option units, of which you take exactly one: Electronics 4, Medical physics 4, Astrophysics 3, Engineering physics 1, Turning points 1. So the number you personally have to carry is 22 to 25. 34 is the size of this catalogue, not the size of anybody’s revision list.
percentage uncertainty = uncertaintyvalue × 100percentage uncertainty = uncertainty/value × 100 phase difference = 2πdλphase difference = 2πd/λ λn = 2Lnλ_n = 2L/n constructive: path difference = nλconstructive: path difference = nλ destructive: path difference = (n + 12)λdestructive: path difference = (n + 1/2)λ d = 1Nd = 1/N specific charge = Qmspecific charge = Q/m E = IVtE = IVt Vout = Vin × R2R1 + R2V_out = V_in × R_2/(R_1 + R_2) Unloaded divider: the output must draw negligible current.
W = pΔVW = pΔV Constant pressure; W is the work done by the gas.
GMmr2 = mv2rGMm/r^2 = mv^2/r T2 = 4π2GM r3T^2 = (4π^2/GM) r^3 vesc = √2GMrv_esc = √(2GM/r) T½ = 0.69RCT_½ = 0.69RC r = mvBQr = mv/BQ v perpendicular to B; non-relativistic, so p = mv.
A = A0e-λtA = A_0e^(-λt) Ek = Qq4πε0rminE_k = Qq/4πε_0r_min ρ = 3u4πR03ρ = 3u/4πR_0^3 fraction kept = (M - mM + m)2fraction kept = ((M - m)/(M + m))^2 I = VS - VZRSI = (V_S - V_Z)/R_S fc = 12πRCf_c = 1/2πRC gain × bandwidth = constantgain × bandwidth = constant fout = fin2nf_out = f_in/2^n a = αra = αr collecting power ∝ D2collecting power ∝ D^2 F = L4πd2F = L/4πd^2 fo = fsvv - vsf_o = f_sv/(v - v_s) Ek = (m − m0)c2E_k = (m − m_0)c^2 d = ct2d = ct/2 Emax = eVE_max = eV I = PAI = P/A relative intensity level = 10 logI2I1relative intensity level = 10 log (I_2/I_1)
MeasurementsYear 121 equations
percentage uncertainty = uncertaintyvalue × 100percentage uncertainty = uncertainty/value × 100 NOT ON THE AQA DATA SHEET: LEARN IT MechanicsYear 1217 equations
moment = F dmoment = F d ON THE AQA DATA SHEET v = ΔsΔt a = ΔvΔtv = (Δs/Δt) a = Δv/Δt ON THE AQA DATA SHEET v = u + atv = u + at ON THE AQA DATA SHEET s = 12(u + v)ts = (1/2)(u + v)t ON THE AQA DATA SHEET s = ut + 12at2s = ut + (1/2)at^2 ON THE AQA DATA SHEET v2 = u2 + 2asv^2 = u^2 + 2as ON THE AQA DATA SHEET F = maF = ma ON THE AQA DATA SHEET W = mgW = mg NOT ON THE AQA DATA SHEET: LEARN IT p = mvp = mv NOT ON THE AQA DATA SHEET: LEARN IT F = Δ(mv)ΔtF = Δ(mv)/Δt ON THE AQA DATA SHEET Ek = p22mE_k = p^2/2m FΔt = Δ(mv)FΔt = Δ(mv) ON THE AQA DATA SHEET W = Fscos θW = Fs cos θ ON THE AQA DATA SHEET P = ΔWΔt = FvP = ΔW/Δt = Fv ON THE AQA DATA SHEET efficiency = useful output powerinput powerefficiency = useful output power/input power ON THE AQA DATA SHEET Ek = 12mv2E_k = (1/2)mv^2 ON THE AQA DATA SHEET ΔEp = mgΔhΔE_p = mgΔh ON THE AQA DATA SHEET MaterialsYear 1210 equations
ρ = mVρ = m/V ON THE AQA DATA SHEET F = kΔLF = kΔL ON THE AQA DATA SHEET energy stored = 12FΔLenergy stored = (1/2)FΔL ON THE AQA DATA SHEET tensile stress = FAtensile stress = F/A ON THE AQA DATA SHEET tensile strain = ΔLLtensile strain = ΔL/L ON THE AQA DATA SHEET E = tensile stresstensile strainE = tensile stress/tensile strain ON THE AQA DATA SHEET p = FAp = F/A Δp = ρA g ΔhA = ρg ΔhΔp = (ρA g Δh)/A = ρg Δh p = ρg hp = ρg h F = 6πηr vF = 6πηr v WavesYear 1222 equations
f = 1Tf = 1/T ON THE AQA DATA SHEET c = fλc = fλ ON THE AQA DATA SHEET phase difference = 2πdλphase difference = 2πd/λ NOT ON THE AQA DATA SHEET: LEARN IT I = I0cos 2θI = I_0cos^2θ λn = 2Lnλ_n = 2L/n NOT ON THE AQA DATA SHEET: LEARN IT v = √Tμv = √(T/μ) f1 = 12L√Tμf_1 = (1/2L)√(T/μ) ON THE AQA DATA SHEET λ1 = 4Lλ_1 = 4L Closed pipe, ideal length: one end closed, end corrections neglected.
λn = 4Lnλ_n = 4L/n Closed pipe: odd harmonics only, n = 1, 3, 5, …
v = 2f(L2 - L1)v = 2f(L_2 - L_1) n = ccsn = c/c_s ON THE AQA DATA SHEET n1 sin θ1 = n2 sin θ2n_1 sin θ_1 = n_2 sin θ_2 ON THE AQA DATA SHEET n = sin θ1sin θ2n = sin θ_1/sin θ_2 sin θc = n2n1sin θ_c = n_2/n_1 ON THE AQA DATA SHEET constructive: path difference = nλconstructive: path difference = nλ NOT ON THE AQA DATA SHEET: LEARN IT destructive: path difference = (n + 12)λdestructive: path difference = (n + 1/2)λ NOT ON THE AQA DATA SHEET: LEARN IT w = λDsw = λD/s ON THE AQA DATA SHEET d sin θ = nλd sin θ = nλ ON THE AQA DATA SHEET d = 1Nd = 1/N NOT ON THE AQA DATA SHEET: LEARN IT P = 1fP = 1/f 1u + 1v = 1f1/u + 1/v = 1/f m = vum = v/u Quantum phenomenaYear 123 equations
hf = φ + Ek(max)hf = φ + E_k(max) ON THE AQA DATA SHEET hf = E1 - E2hf = E_1 - E_2 ON THE AQA DATA SHEET λ = hmvλ = h/mv ON THE AQA DATA SHEET ParticlesYear 122 equations
specific charge = Qmspecific charge = Q/m NOT ON THE AQA DATA SHEET: LEARN IT E = hf = hcλE = hf = hc/λ ON THE AQA DATA SHEET ElectricityYear 1214 equations
I = ΔQΔtI = ΔQ/Δt ON THE AQA DATA SHEET V = WQV = W/Q ON THE AQA DATA SHEET I = nAvqI = nAvq R = VIR = V/I ON THE AQA DATA SHEET ρ = RALρ = RA/L ON THE AQA DATA SHEET RT = R1 + R2 + R3 + …R_T = R_1 + R_2 + R_3 + … ON THE AQA DATA SHEET 1RT = 1R1 + 1R2 + 1R3 + …1/R_T = 1/R_1 + 1/R_2 + 1/R_3 + … ON THE AQA DATA SHEET E = IVtE = IVt NOT ON THE AQA DATA SHEET: LEARN IT P = IV = I2R = V2RP = IV = I^2R = V^2/R ON THE AQA DATA SHEET Vout = Vin × R2R1 + R2V_out = V_in × R_2/(R_1 + R_2) NOT ON THE AQA DATA SHEET: LEARN IT Unloaded divider: the output must draw negligible current.
Vx = VxLV_x = V(x/L) E1E2 = l1l2E_1/E_2 = l_1/l_2 ε = EQε = E/Q ON THE AQA DATA SHEET ε = I(R + r)ε = I(R + r) ON THE AQA DATA SHEET Periodic motionYear 1311 equations
ω = vr = 2πfω = v/r = 2πf ON THE AQA DATA SHEET a = ΔvΔt = vΔθΔθ/ω = vωa = Δv/Δt = vΔθ/(Δθ/ω) = vω a = v2r = ω2ra = v^2/r = ω^2r ON THE AQA DATA SHEET F = mv2r = mω2rF = mv^2/r = mω^2r ON THE AQA DATA SHEET a = -ω2xa = -ω^2x ON THE AQA DATA SHEET x = Acos (ωt)x = A cos(ωt) ON THE AQA DATA SHEET v = ±ω√A2 - x2v = ±ω√(A^2 - x^2) ON THE AQA DATA SHEET T = 2π√mkT = 2π√(m/k) ON THE AQA DATA SHEET T = 2π√lgT = 2π√(l/g) ON THE AQA DATA SHEET E = 12kA2E = (1/2)kA^2 E = 12mω2x02E = (1/2)mω^2x_0^2 Thermal physicsYear 138 equations
Q = mcΔθQ = mcΔθ ON THE AQA DATA SHEET P1 − P2 = (m1 − m2)cΔθP_1 − P_2 = (m_1 − m_2)cΔθ Q = mlQ = ml ON THE AQA DATA SHEET pV = nRTpV = nRT ON THE AQA DATA SHEET pV = NkTpV = NkT ON THE AQA DATA SHEET W = pΔVW = pΔV NOT ON THE AQA DATA SHEET: LEARN IT Constant pressure; W is the work done by the gas.
pV = 13Nm(crms)2pV = (1/3)Nm(c_rms)^2 ON THE AQA DATA SHEET 12m(crms)2 = 3kT2 = 3RT2NA(1/2)m(c_rms)^2 = 3kT/2 = 3RT/2N_A ON THE AQA DATA SHEET Gravitational fieldsYear 139 equations
F = Gm1m2r2F = Gm_1m_2/r^2 ON THE AQA DATA SHEET g = Fmg = F/m ON THE AQA DATA SHEET g = GMr2g = GM/r^2 ON THE AQA DATA SHEET V = -GMrV = -GM/r ON THE AQA DATA SHEET ΔW = mΔVΔW = mΔV ON THE AQA DATA SHEET g = -ΔVΔrg = -ΔV/Δr ON THE AQA DATA SHEET GMmr2 = mv2rGMm/r^2 = mv^2/r NOT ON THE AQA DATA SHEET: LEARN IT T2 = 4π2GM r3T^2 = (4π^2/GM) r^3 NOT ON THE AQA DATA SHEET: LEARN IT vesc = √2GMrv_esc = √(2GM/r) NOT ON THE AQA DATA SHEET: LEARN IT Electric fieldsYear 137 equations
F = 14πε0 Q1Q2r2F = (1/4πε_0) (Q_1Q_2/r^2) ON THE AQA DATA SHEET E = FQE = F/Q ON THE AQA DATA SHEET E = VdE = V/d ON THE AQA DATA SHEET E = 14πε0 Qr2E = (1/4πε_0) (Q/r^2) ON THE AQA DATA SHEET V = 14πε0 QrV = (1/4πε_0) (Q/r) ON THE AQA DATA SHEET ΔW = QΔVΔW = QΔV ON THE AQA DATA SHEET E = ΔVΔrE = ΔV/Δr ON THE AQA DATA SHEET CapacitanceYear 139 equations
C = QVC = Q/V ON THE AQA DATA SHEET C = 4πε0rC = 4πε_0r C = Aε0εrdC = Aε_0ε_r/d ON THE AQA DATA SHEET E = 12QV = 12CV2 = 12Q2CE = (1/2)QV = (1/2)CV^2 = (1/2)(Q^2/C) ON THE AQA DATA SHEET C = C1 + C2 + …C = C_1 + C_2 + … 1C = 1C1 + 1C2 + …1/C = 1/C_1 + 1/C_2 + … T½ = 0.69RCT_½ = 0.69RC NOT ON THE AQA DATA SHEET: LEARN IT Q = Q0e-t/RCQ = Q_0e^(-t/RC) ON THE AQA DATA SHEET Q = Q0(1 - e-t/RC)Q = Q_0(1 - e^(-t/RC)) ON THE AQA DATA SHEET Magnetic fieldsYear 1314 equations
F = BIlF = BIl ON THE AQA DATA SHEET F = BIl sin θF = BIl sin θ F = BQvF = BQv ON THE AQA DATA SHEET F = BQv sin θF = BQv sin θ r = mvBQr = mv/BQ NOT ON THE AQA DATA SHEET: LEARN IT v perpendicular to B; non-relativistic, so p = mv.
VH = BIntqV_H = BI/ntq Φ = BAΦ = BA ON THE AQA DATA SHEET B uniform and along the normal to the area A.
NΦ = BANcos θNΦ = BAN cos θ ON THE AQA DATA SHEET ε = NΔΦΔtε = N(ΔΦ/Δt) ON THE AQA DATA SHEET ε = BANωsin ω tε = BANω sin ω t ON THE AQA DATA SHEET Irms = I0√2I_rms = I_0/√(2) ON THE AQA DATA SHEET Vrms = V0√2V_rms = V_0/√(2) ON THE AQA DATA SHEET NsNp = VsVpN_s/N_p = V_s/V_p ON THE AQA DATA SHEET efficiency = IsVsIpVpefficiency = I_sV_s/I_pV_p ON THE AQA DATA SHEET Nuclear physicsYear 1311 equations
I = kx2I = k/x^2 ON THE AQA DATA SHEET ΔNΔt = -λNΔN/Δt = -λN ON THE AQA DATA SHEET A = λNA = λN ON THE AQA DATA SHEET N = N0e-λtN = N_0e^(-λt) ON THE AQA DATA SHEET T½ = ln 2λT_½ = (ln 2)/λ ON THE AQA DATA SHEET A = A0e-λtA = A_0e^(-λt) NOT ON THE AQA DATA SHEET: LEARN IT Ek = Qq4πε0rminE_k = Qq/4πε_0r_min NOT ON THE AQA DATA SHEET: LEARN IT R = R0A1/3R = R_0A^(1/3) ON THE AQA DATA SHEET ρ = 3u4πR03ρ = 3u/4πR_0^3 NOT ON THE AQA DATA SHEET: LEARN IT E = mc2E = mc^2 ON THE AQA DATA SHEET fraction kept = (M - mM + m)2fraction kept = ((M - m)/(M + m))^2 NOT ON THE AQA DATA SHEET: LEARN IT ElectronicsYear 1313 equations
I = VS - VZRSI = (V_S - V_Z)/R_S NOT ON THE AQA DATA SHEET: LEARN IT f0 = 12π√LCf_0 = 1/2π√(LC) ON THE AQA DATA SHEET Q = f0fBQ = f_0/f_B ON THE AQA DATA SHEET fc = 12πRCf_c = 1/2πRC NOT ON THE AQA DATA SHEET: LEARN IT Vout = AOL(V+ - V-)V_out = A_OL(V_(+) - V_(-)) ON THE AQA DATA SHEET VoutVin = -RfRinV_out/V_in = -R_f/R_in ON THE AQA DATA SHEET VoutVin = 1 + RfR1V_out/V_in = 1 + R_f/R_1 ON THE AQA DATA SHEET gain × bandwidth = constantgain × bandwidth = constant NOT ON THE AQA DATA SHEET: LEARN IT Vout = -Rf(V1R1 + V2R2 + V3R3 + ...)V_out = -R_f(V_1/R_1 + V_2/R_2 + V_3/R_3 + ...) ON THE AQA DATA SHEET Vout = (V+ - V-)RfR1V_out = (V_(+) - V_(-))(R_f/R_1) ON THE AQA DATA SHEET fout = fin2nf_out = f_in/2^n NOT ON THE AQA DATA SHEET: LEARN IT AM bandwidth = 2fMAM bandwidth = 2f_M ON THE AQA DATA SHEET FM bandwidth = 2(Δf + fM)FM bandwidth = 2(Δf + f_M) ON THE AQA DATA SHEET Engineering physicsYear 1325 equations
a = αra = αr NOT ON THE AQA DATA SHEET: LEARN IT ω2 = ω1 + αtω_2 = ω_1 + αt ON THE AQA DATA SHEET ω22 = ω12 + 2αθω_2^2 = ω_1^2 + 2αθ ON THE AQA DATA SHEET θ = ω1t + αt22θ = ω_1t + αt^2/2 ON THE AQA DATA SHEET θ = (ω1 + ω2)t2θ = ((ω_1 + ω_2)t)/2 ON THE AQA DATA SHEET I = m1r12 + m2r22 + …I = m_1r_1^2 + m_2r_2^2 + … ON THE AQA DATA SHEET Ek = 12Iω2E_k = (1/2)Iω^2 ON THE AQA DATA SHEET T = FrT = Fr ON THE AQA DATA SHEET T = IαT = Iα ON THE AQA DATA SHEET angular momentum = Iωangular momentum = Iω ON THE AQA DATA SHEET TΔt = Δ(Iω)TΔt = Δ(Iω) ON THE AQA DATA SHEET W = TθW = Tθ ON THE AQA DATA SHEET P = TωP = Tω ON THE AQA DATA SHEET Q = ΔU + WQ = ΔU + W ON THE AQA DATA SHEET W = pΔVW = pΔV ON THE AQA DATA SHEET Constant pressure; W is the work done by the gas.
pV = constantpV = constant ON THE AQA DATA SHEET pVγ = constantpV^γ = constant ON THE AQA DATA SHEET efficiency = WQH = QH − QCQHefficiency = W/Q_H = (Q_H − Q_C)/Q_H ON THE AQA DATA SHEET maximum theoretical efficiency = TH − TCTHmaximum theoretical efficiency = (T_H − T_C)/T_H ON THE AQA DATA SHEET input power = calorific value × fuel flow rateinput power = calorific value × fuel flow rate ON THE AQA DATA SHEET indicated power = area of loop × cycles per second × cylindersindicated power = area of loop × cycles per second × cylinders ON THE AQA DATA SHEET P = TωP = Tω ON THE AQA DATA SHEET friction power = indicated power − brake powerfriction power = indicated power − brake power ON THE AQA DATA SHEET COPref = QCW = QCQH − QCCOP_ref = Q_C/W = Q_C/(Q_H − Q_C) ON THE AQA DATA SHEET COPhp = QHW = QHQH − QCCOP_hp = Q_H/W = Q_H/(Q_H − Q_C) ON THE AQA DATA SHEET AstrophysicsYear 1313 equations
M = fofeM = f_o/f_e ON THE AQA DATA SHEET θ ≈ λDθ ≈ λ/D ON THE AQA DATA SHEET collecting power ∝ D2collecting power ∝ D^2 NOT ON THE AQA DATA SHEET: LEARN IT F = L4πd2F = L/4πd^2 NOT ON THE AQA DATA SHEET: LEARN IT p = 1dp = 1/d m − M = 5 logd10m − M = 5 log (d/10) ON THE AQA DATA SHEET P = σA T4P = σA T^4 ON THE AQA DATA SHEET λmax T = 2.9 × 10−3 m Kλ_max T = 2.9 × 10^(−3) m K ON THE AQA DATA SHEET Rs ≈ 2GMc2R_s ≈ 2GM/c^2 ON THE AQA DATA SHEET fo = fsvv - vsf_o = f_sv/(v - v_s) NOT ON THE AQA DATA SHEET: LEARN IT Δff = vcΔf/f = v/c ON THE AQA DATA SHEET Approximation for v much less than c.
z = Δλλz = Δλ/λ ON THE AQA DATA SHEET v = Hdv = Hd ON THE AQA DATA SHEET Turning pointsYear 1310 equations
eV = 12mv2eV = (1/2)mv^2 ON THE AQA DATA SHEET QVd = mgQV/d = mg ON THE AQA DATA SHEET F = 6π ηrvF = 6πηrv ON THE AQA DATA SHEET c = 1√μ0ε0c = 1/√(μ_0ε_0) ON THE AQA DATA SHEET p = hλp = h/λ ON THE AQA DATA SHEET λ = h√2meVλ = h/√(2meV) ON THE AQA DATA SHEET t = t0√1 − v2/c2t = t_0/√(1 − v^2/c^2) ON THE AQA DATA SHEET l = l0√1 − v2/c2l = l_0√(1 − v^2/c^2) ON THE AQA DATA SHEET E = mc2 = m0c2√1 − v2/c2E = mc^2 = m_0c^2/√(1 − v^2/c^2) ON THE AQA DATA SHEET Ek = (m − m0)c2E_k = (m − m_0)c^2 NOT ON THE AQA DATA SHEET: LEARN IT Medical physicsYear 1314 equations
d = ct2d = ct/2 NOT ON THE AQA DATA SHEET: LEARN IT Z = ρcZ = ρc ON THE AQA DATA SHEET IrI0 = (Z2 - Z1)2(Z2 + Z1)2I_r/I_0 = ((Z_2 - Z_1)^2)/((Z_2 + Z_1)^2) ON THE AQA DATA SHEET I = I0e-μxI = I_0e^(-μx) Δff = 2v cos θcΔf/f = (2v cos θ)/c Emax = eVE_max = eV NOT ON THE AQA DATA SHEET: LEARN IT I = I0e-μxI = I_0e^(-μx) ON THE AQA DATA SHEET μm = μρμ_m = μ/ρ ON THE AQA DATA SHEET P = 1fP = 1/f ON THE AQA DATA SHEET 1u + 1v = 1f1/u + 1/v = 1/f ON THE AQA DATA SHEET m = vum = v/u ON THE AQA DATA SHEET I = PAI = P/A NOT ON THE AQA DATA SHEET: LEARN IT intensity level = 10 logII0intensity level = 10 log (I/I_0) ON THE AQA DATA SHEET relative intensity level = 10 logI2I1relative intensity level = 10 log (I_2/I_1) NOT ON THE AQA DATA SHEET: LEARN IT
213 equations in total. 34 of them are off the AQA data sheet across every option together, which is 22 to 25 for any one student. See also key ideas, command words and the revision checklist.