EinH- EQUATIONS

• Frequency equation


  Frequency = 1/period(s)

  (Hz)
• Power equation


  Power = energy/time

  (W) (J) (s)

  OR

  Power = current x voltage

  (W) (A) (V)
• Electric current

  Charge = current x time

  (C) (A) (s)

  (Q=It)
• Electrical power

  Power = current^2 x resistance

  (W) (A^2) (Ohms)

  (P= I^2 X R)
• Electrical energy

  Energy = charge x potential difference

  (J) (C) (V)

  (E= Q X V)
• Electrical energy 2

  Energy = current x time x p.d

  (J) (A) (s) (V)

  ( E = ItV)
• Electrical energy - COST OF ELECTRICITY

  Electrical energy = power x time

  (kWh) (kW) (h)
• Cost to use electrical appliance

  Total cost = number of kWh x cost per kWh

  (pence) (kWh) (pence)
• thickness in sankey diagram

  1 square = amount of energy / no. of squares (width)
• Efficiency

  Efficiency = useful energy OUT/ total energy IN