Kirchhoff’s Laws—

Kirchhoff gave two laws

1. Kirchhoff’s First law or Junction Law or Kirchhoff’s Current Law (KCL)
2. Kirchhoff’s Second Law or Loop Law or Kirchhoff’s Voltage Law (KVL)

Kirchhoff’s First law or Junction Law or Kirchhoff’s Current Law (KCL)

This law states that at a junction, the algebraic sum of all the currents is zero. In other words at a junction the sum of all the incoming currents is equal to the sum of all the outgoing currents

Sensitivity of a Potentiometer-

A potentiometer is sensitive if it shows a significant change in balancing length for a small change in the potential difference.

Sensitivity is of two types

1. Voltage sensitivity    
2. Current sensitivity

Voltage sensitivity—

It is defined as the change in potential gradient per unit change in voltage difference across the ends of potentiometer wire.

 Current sensitivity—

Combination of Resistors—

Resistors are combined in two manner

1. Series Combination
2. Parallel combination

Series Combination of Resistor—        

When resistors are arranged such that first end of one resistor is connected to the one point and the second one is connected to the first end of the second resistor and second resistor is connected to third resistor and so on, the arrangement is called series combination.

Classification of Material—

Conductor—

The material which conduct electric current fairly well are called conductor.

Insulator—

The material which do not conduct electric current are called insulator.

Semiconductor—

These are the materials whose resistivities lie in between those of conductor and insulator.

Carriers of Current—

The charged particles which by flowing in a definite direction set up an electric current are called current carriers.