CHARGE AND ELECTRIC FIELD

Electric Charge is the property of subatomic particles that causes it to experience a force when placed in an electric and magnetic field.”

Electric charges are of two types: Positive and Negative, commonly carried by charge carriers protons and electrons.

Examples of the types of charges are subatomic particles or the particles of matter:

➤Protons are positively charged.

➤Electrons are negatively charged.

➤Neutrons have zero charge.

Electric Charge a Vector Quantity

Electric charge is a scalar quantity. Apart from having a magnitude and direction, a quantity to be termed a vector should also obey the laws of vector addition, such as triangle law of vector addition and parallelogram law of vector addition; only then the quantity is said to be a vector quantity. When two currents meet at a junction, in the case of an electric current, the resultant current of these will be an algebraic sum and not the vector sum. Therefore, an electric current is a scalar quantity, although it possesses magnitude and direction.

Coulomb is the unit of electric charge.One coulomb is the quantity of charge transferred in one sec.

One coulomb of charge is that charge which when placed at rest in vacuum at a distance of one metre from an equal and similar stationary charge repels it and is repelled by it with a force of 9 x 109 newton.

(Other unit of charge are faraday and ampere-sec)

Negative Charge

When an object has a negative charge it means that it has more electrons than protons.

Positive Charge

When an object has a positive charge it means that it has more protons than electrons.

(When there is an identical number of positive and negative charges, the negative and positive charges would cancel out each other and the object would become neutral)

How an object can be charged

An uncharged object can be charged in three different ways as follows:

• Charging by friction ( triboelectric charging)
• Charging by conduction
• Charging by induction