# Important Formulae to remember for O Levels Physics Electricity Topics

Here are some important formulae related to electricity for O Levels Physics Singapore:

Electrical Energy (E) = Power (P) x Time (t) E = P x t

Power (P) = Voltage (V) x Current (I) P = V x I

Voltage (V) = Current (I) x Resistance (R) V = I x R

Resistance (R) = Voltage (V) / Current (I) R = V / I

Ohm's Law: Current (I) = Voltage (V) / Resistance (R) I = V / R

Electrical Power (P) = Current (I)^2 x Resistance (R) P = I^2 x R or = V^2/R

Electromotive Force (E) = Charge (Q) x Voltage (V) E = Q x V

Charge (Q) = Current (I) x Time (t) Q = I x t

Potential Difference (V) = Work done (W) / Charge (Q) V = W / Q

Electrical Power (P) = Work done (W) / Time (t) P = W / t

Resistance (R) = Resistivity (ρ) x Length (L) / Cross-sectional area (A) R = ρL / A

Note: In these formulae, the units used are SI units (i.e., joules, watts, volts, amperes, ohms, meters, and seconds).

Tip: You can write these down in a cheat sheet and bring it everywhere with you whenever you are doing your homework or revision!

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