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ELECTRICAL ENERGY AND POWER

CONTENT

  1. Electrical Energy
  2. Electrical Power
  3. Electric Meter Reading and Billing
  4. Fuse and Circuit Breaker

 

Electrical Energy

If Q coulombs of electricity flows between two points whose potential difference is V volts, then the work done (W) is given by

\(W = QV \\ Joules = Coulomb \times Volts\)

But \(Q = It\)

Substituting \(Q = It; \\ W = (It)V \\ W = IVt\)

Also substituting \(V = IR\) from Ohms law

\(W = I^2Rt\)

Or substituting for \(I = \frac{V}{R} \\ W = \frac{V^2}{R}t\)

Electrical energy \(E = IVt \\ E = I^2Rt \\ E = \frac{V^2}{R}t\)

 

Electrical Power (P)

Power is defined as the time rate of doing work.

\(Power = \frac{Energy}{Time} \\ Power = \frac{VIt}{t} \\ P = IV \\ P = I^2R \\ I = \frac{V^2}{R} \\ P = \frac{E}{t}\)

 

Electric Meter Reading and Billing

To measure or read electricity consumed in order to bill the consumer accordingly, the standard unit commonly used is the kilowatt/hour.

Lesson tags: Physics Lesson Notes, Physics Objective Questions, SS1 Physics, SS1 Physics Evaluation Questions, SS1 Physics Evaluation Questions Third Term, SS1 Physics Objective Questions, SS1 Physics Objective Questions Third Term, SS1 Physics Third Term
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