Resistance - Ohm's Law and Kirchhoff's Laws

• The amount of energy transferred to a load depends on two things: 1. the potential difference of the power supply and 2. the resistance of the pathway through the loads that are using the lectir potential energy.
• Resistance directly affect the amount of current passes through the load. Low resistance makes current to pass through the load much more easily.
• The measure of the opposition to flow is called electrical resistane.
• R = V/I is the formula for calculating resistance. R is the resistance in volts/ampere and unit is Ω. V is the potential difference in volts and I is the current in amperes.
• The Ohm's law states that the V/I ratio is constant for a particular resistor.
• The amount of current flowing through a resistor varies directly as the amount of poetential difference applied across the resistor. The higher the potential difference, the more the current flows through the resistor.
• The resistance on a conductor depends on many properties such as Length, corss-sectional area, the material it is made of, and its temperture.
• The formula for calculating the resistance of  conductors in difference length  R1/R2 = L1/L2.  
• Cross-sectional area that affects the resistance, the larger the area or thicker the conductor, the less resistant it has to current flow. It is represented as R1/R2 = A2/A1
• Some materials are better conductors than other materials. The measure of the resistance of a substance is called resistivity. It has units Ω m. It is represented as R1/R2 = p1/p2
• Temperature also works as one factor that changes resistance of a substance. Unsually the higher the temperature the higher the resistance, however, not for all substances.