# Formulae of Class X Physics from Electricity and Magnetic Effects of Current

4:10 pmClas X is the first phase for every student to face the burden of a national level competition. Here Oureducation.in is helping you to revise and keep notes of some important formulae, topics and chapters. The post describes some formulae of Class X physics from chapters **Electricity **and** Magnetic Effects of Current, **these being few of the most important chapters for boards.

## CHAPTER- Electricity

**Formula 1:
Coulomb’s Law **=(Q1*Q2)/(r*r)k ; where k= constant, Q1, Q2 are the charges on bodies 1 and 2.

**Formula 2:**

Conduction current ( I ) = dQ/dt ; where Q= charge and t = time, dQ=charge on the body for very short interval of time dt

**Formula 3:**

Constant current ( I ) = Q/t ; where Q= charge and t= time

**Formula 4:**

Current density ( J ) = I/ A ; where I= current and A= area in square meter

**Formula 5:**

Electric Power ( P ) = V/I ; where V= voltage and I= current

**Formula 6:**

Conductance ( G ) = 1/ R ; where R = resistance of the body

**Formula 7:**

Ohm’s Law = V= IR ; where V= voltage, I = current and R= resistance of the body

**Formula 8:**

Series connection of resistors, Req =( R1+ R2 + R3 +….+ Rn) ; where R1, R2, R3 — Rn are the respective resistances of “n” number of bodies.

**Formula 9:**

Parallel connection of resistors, Req = (1/R1 + 1/R2 + 1/R3 +…+ 1/Rn) ; where R1, R2, R3 — Rn are the respective resistances of “n” number of bodies.

**Formula 10:**

Electric work done = U I t = UQ ; where U= potential energy , Q= charge, I = curent and t=time

**Formula 11:**

Thermal emission = j = AT*T exp(-Wa/kT)

**Formula 12:**

Force in electric field ( F) = E .Q ; where E= Electric Field and Q= Charge on body

**Formula 13:**

Voltage in plate capacitor = V= Ed ; where E= Electric Field and d= distance vector

**Formula 14:**

Energy of particle accelerated in an electric field ( E ) = QU

**Formula 15:**

Effective current in AC circuit = I = Ieff/ ( 2 ) ^1/2

**Formula 16:**

Effective voltage in AC circuit = V = Veff / (2 )^ 1/2

**Formula 17:**

Ohm’s law in a.c. circuit , V= IZ ; where I = current, V= voltage and Z= impedance

**Formula 18:**

Thomsons equation, w = (1/LC )^ (1/2) ; where L=inductance, W=Work Done and C = Capacitance.

## CHAPTER- Magnetic Effects of Current

**Formula 1:**

**B (inversely proportional) (I/r)** ; where B= Strength of Magnetic Field, I=current passed through conductor and r=distance from conductor

**Formula 2:
**B=(µI/2πr) where B= Strength of Magnetic Field, r= distance from conductor, I=current passed through conductor and µ= permeability of medium

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