AIM OF THE EXPERIMENT
Confirmation of OHM’S LAW
It was George Simon Ohm (1787-1854) who established experimentally that the current in a metal wire is directly proportional to the potential difference V applied to its two ends, provided that the physical conditions such as temperature remain constant:
Exactly how much current flows in a wire depends not only on the voltage, but also on the resistance the wire offers to the flow of electrons. Electrons are showed down because of interactions with the atoms of the wire. The higher the resistance, the less the current for a given voltage V. Resistance is defined as;
Where R is the resistance of a wire or any other device, V is the potential difference across the device and I is the current that flows through it. This result is known as Ohm’s law. In this experiment by using equipment circuit experiment board and resistor, we will experimentally verify the Ohm’s Law.
* I was given a resistor. First of all, I determined the resistance of each resistor from the color codes by using method defined in and wrote my results into the Table. * I constructed the circuit by using circuit experimental board, DC power supply the resistors. * I adjusted the voltage of DC power supply to a suitable value and kept it constant. Also measured the current and the voltage by using the suitable scale and wrote my results into the table. * I choose one of the resistors and connected the circuits given. * Finally I plotted the graph voltages versus current. And calculated the resistance from the graph.
R = 150 Ω
Voltage (v)| Current (mA)|
y₁ = 1.5, y₂ = 12.6, x₁ = 10.0, x₂ = 87.0
Slope = y₂ – y₁/x₂ – x₁
= 12.6 – 1.5/87.0 – 10.0
= 11.1v/77.0 mA
= 144.16 Ω.
* Power Source