Ohm’s law investigation
M5W, lab report assignment
This investigation will be looking into the rules of ohm’s law. Ohm’s law is the basic explanation of the relationship between: Voltage, current and resistance, as this law states that, a resistance is inversely proportional to a current, for example if you increase the resistance the current will decrease or if you decrease the resistance this will increase the current. Furthermore, the voltage will always be proportional to the current. However, to explain these general rules a formulae is constructed as I represents current, which is measured in amps, as R represent the resistance, which is measured in ohms (), will always equal to the v, which is voltage measured in volts.
Research question: This investigation will explore the affect a voltage (V) has on a currents flow, within a series circuit, a series circuit is a circuit where by the current only has one path way to follow.
Aim: My aim for this investigation is to investigate, how an increasing voltage can affect the flow of a current within a series circuit.
Hypothesis: For this experiment, I predict that, using the rules for ohm’s law, the current that will flow through a conductor is proportional to the potential difference. Therefore, when a voltage, the pushing force in a circuit is increasing or decreasing the electrical flow (current) will automatically equal to the potential difference, thus resulting in the current to change as proportional to the voltage, due to the fact only a resistance increasing will affect the current to decrease, as they are inversely proportional.
Variables: Independent: in this investigation the voltage (v, volts) will be changed.
Controlled: in this experiment the resistance () will be kept the same i.e. the bulb in the circuit.
Dependant: lastly, the current (I, amps) will be measured.
Materials list:
Power unit source (volts)
Digital ammeter (amps)
Light bulb ( the resistor)
Wires(a connector, allowing current to flow from one end of the circuit to the other)
Metal clips (conductor)
Table for results
Method:
1. Firstly, for this investigation prepare all the apparatus. To do this, plug in the power source and connect one of your wires to the bulb with the metal conductors clipped on each end of the wires, making sure not to put you ammeter in parallel to a component, so that the current can pass through.
2. Secondly, attach one of the wires to the bulb which will be the controlled variable in this experiment, therefore keep it the same throughout the experiment. After connect the other wire from the power source to the multi meter which will be measuring the currents flow in amps, which will be your dependant variable, make sure to set the multi meter to “amps” to get valid readings.
3. After that, draw out you table of results with one column including the six sets of goes which will be taken in each three trials.
4. Next, for this experiment the voltage which will be your independent variable the one you will be changing, will only be increasing each time by two. Therefore, the voltage will start from, 2 then proceeded onwards to, 4, 6,8,10 and lastly 12.
5. Lastly, as you are changing the independent variable, make sure you are measuring your dependant variable the current (amps) for each volt, using the digital ammeter plugged into the circuit, by reading the digital results. Also make sure your controlled variable stays controlled at all times, so that the resistor does not have an effect on your experiment.
6. Repeat this method out for three times in order to obtain fair result and to ensure that your experiment is accurate. After you have repeated the experiment tree times, make sure you find the averages of each of current, by dividing the voltage (volts) and the average currents (amps).
Diagram of apparatus:
