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# Electricity Formulas

Electricity is the flow of charge from anode to cathode in a conductor. Electricity has wide applications It acts as a tool for providing power to the electrical devices. In simple words we can say the flow of charge builds up the current which we call Electricity. To under stand how the Electricity is produced we need to understand the various parameters related to it like voltage, Current, resistance, resistivity, conductivity and relation between them.

Here are given some commonly used Electricity formula and also the pictorial representation which may be helpful for you.

 Quantity Formulas Unit Current I I = $\frac{Q}{t}$                 Q = Charge t = time taken Amperes (A) Voltage V V = $\frac{E}{Q}$ orV = $\frac{W}{Q}$E = Energy, W = Work done Volts (V) Resistance R R = $\frac{\rho l}{A}$  $\rho$ = Resistivity, l = length, A = Area Ohm ($\Omega$) Resistance R R = $\frac{V}{I}$ ohm ($\Omega$) Power P P = VI Watts (W) Conductivity $\sigma$ $sigma$ = $\frac{1}{\rho}$ Siemens per meter (S/m)

Electricity Formulas are useful in getting the unknown electrical parameters from the known one in an electrical circuits.

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## Electricity Problems

Below are given problems based on electricity which may be helpful for you.

### Solved Examples

Question 1: Calculate the current flowing through the electric heater have p.d of 220 V and resistance is 60 $\Omega$.
Solution:

Given: Resistance R = 60 $\Omega$, Voltage V = 220 V,
The current is given by I = $\frac{V}{R}$
= $\frac{220}{60}$
= 3.667 A.

Question 2: An electrical lamp lights for 3 hours and draws a current of 0.5 A. What is the amount of charge flowing through the lamp?
Solution:

Current I = 0.5 A,
Time taken t = 3 hours = 3 $\times$ 3600 = 10800 s,
Charge Q = I $\times$ t = 0.5 $\times$ 10800 = 5400 C

 More topics in Electricity Formulas Electric Current Formula Electric Power Formula Gauss Law Formula Surface Charge Density Formula Charge Density Formula Volume Charge Density Formula Parallel Plate Capacitor Formula Cylindrical Capacitor Formula Energy Consumption Formula
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