Grade 12 Physics Assignment

Physics assignment

Aim

To determine which factors affect the resistance of a conductor, and the mathematical relationship that exists between these variables.

Hypothesis

• Copper wires would be a better conductor than nichrome wires because it would yield less resistance when they have same cross-sectional area, length and temperature.

• Resistance would be increased when length wires increased.

• Resistance would be increased when cross-sectional area of wires decreased.

• Resistivity of wires is a factor of affecting the resistance.

Background information

Electrical resistance

Electrical resistance is a measure of the degree to which an object opposes the passage of an electric current. The SI unit of electrical resistance is the ohm.

(“Electrical Resistance” http://en.wikipedia.org/wiki/Electrical_resistance)

Electrical resistance is the measure of the degree that a substance against to the electric current through it in an electric circuit. Good conductors are associated with low resistance and poor conductors are associated with high resistance. Resistance depends on many factors. There are 4 main factors. They are the resisitivity of the metal, the length of the conductor, cross-sectionalal area of the conductor and the temperature of the conductor. To make these factors more specific, they can include the nature of the material (electrical resistivity), conductor’s temperature, dimensions, and thermal properties; degree of impurity; the nature and state of illumination of the surface; and the frequency and magnitude of the current.

Electrical resistivity

The definition from wikipedia of electrical resistivity is:

Electrical resistivity (also known as specific electrical resistance) is a measure of how strongly a material opposes the flow of electric current. A low resistivity indicates a material that readily allows the movement of electrical charge. The SI unit of electrical resistivity is the ohm meter....