Definitions [3]
Definition: EMF of a Cell
The emf of a cell is defined as the work done in carrying a unit positive charge through the complete circuit, including the charge flow inside the cell.
Unit: J/C (or) volt
Definition: Internal Resistance of a Cell
The resistance offered by the electrolyte of the cell when an electric current flows through it is known as internal resistance.
Definition: Terminal Potential Difference (V)
When current is drawn through a cell or current is supplied to it, then the potential difference across its terminals is called the terminal potential difference.
\[V=E-Ir\]
Key Points
Key Points: Parallel Combination of Resistors
- In parallel, resistors are connected across the same two points (multiple paths).
- Voltage is the same across all resistors.
Equivalent resistance:
\[\frac{1}{R_{eq}}=\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}+\cdots\]
For n identical resistors:
Req = R/n
Current relation:
I = I₁ + I₂ + I₃
Current divider rule:
I₁ : I₂ : I₃ = \[\frac{1}{R_{1}}:\frac{1}{R_{2}}:\frac{1}{R_{3}}\]
Req < Rmin
