Units

Units in Electricity

Basic Units

  • Ampere (A) is the SI unit of electric current. A current of one ampere means that one coulomb of electric charge is flowing per second.

  • Volt (V) is the SI unit of voltage (also known as electric potential difference). One volt is defined as the difference in electric potential that would drive one ampere of current against one ohm of resistance.

  • Ohm (Ω) is the SI unit of electrical resistance. One ohm is the resistance that will allow one volt to drive a current of one ampere.

  • Watt (W) is the SI unit of power. Power is the rate at which energy is transferred, used, or transformed. One watt is equivalent to one joule per second.

Derived Units

  • Coulomb (C) is the SI unit of electric charge. One coulomb is defined as the amount of charge transported by a constant current of one ampere in one second.

  • Joule (J) is the SI unit of energy. It is defined as the amount of work done or energy transferred by a force of one newton exerting over a distance of one metre. For electricity, one joule is equivalent to one watt-second.

Conversion Factors

  • 1 joule per second is equal to 1 watt of power.

  • 1 ampere traffic for 1 second carries 1 coulomb of charge.

  • 1 volt across a resistance of 1 Ω will drive a 1 ampere current.

Equations and Relationships

  • Ohm’s Law: Current (I) is equal to voltage(V) divided by resistance(R). This is represented as I = V/R.

  • Power relationship: Power (P) in watts is equal to voltage (V) multiplied by current (I). This is represented as P = V*I.

  • Energy relationship: Energy (E) in joules is equal to power (P) multiplied by time (t). The formula for this is E = P*t.

  • Charge-Current-Time relationship: The total electric charge (Q) transferred is equal to the current (I) multiplied by time (t). The formula for this is Q = I*t.

Must remember to apply these concepts and formulas correctly for solving problems related to electricity.