- Level: International Baccalaureate
- Subject: Physics
- Word count: 1893
design of a variable resistor
Extracts from this document...
Introduction
International School of Phnom Penh 5199
Candidate name: HOZUMI Haruka Page of
Candidate Number Science
Design of a Variable Resistor
Aim: Our aim is to find the most suitable length and thickness of wire for the variable resistor with a broken wire. We will determine the difference in resistance between three copper wires with different diameter, and three wires with different lengths (10cm, 15 cm 20 cm).
We chose these lengths. We thought that three different lengths would be enough to
Hypothesis:
Diameter: We think that larger the diameter of copper wire, it will have more resistance because copper wire generally has higher resistance. Since it is largest, it will have more resistance.
Length: We think that the longer the wire, the resistance will be higher because the electricity has to travel longer distance.
We think that
We chose these diameters because
Apparatus:
- Copper wires (3 diameter size, all 10cm)
- Copper wires (3 different lengths – 10cm, 15cm, 20cm)
- Power cell
- Ammeter
- Variable resistor
- Volt meter
- Wires (to connect)
- Scissor
- Ruler
- Calculator
- Crocodile clips
Independent variables:
- Diameter of wires – for testing diameter
- Lengths of wires – for testing lengths
Controlled Variables:
- Length of the wires (for testing diameter) – we will make the wires as straight as we can, and use a ruler to cut them in same size (length). The lengths have to be same because if it is different, the test would not be fair.
- Diameter of the wires (for testing lengths) – we will use the same type (size). The diameters have to be same because if it is different, the test would not be fair.
- All the wires should be straight so that the electricity can travel easy.
- Voltage – we will keep the power cell to 3 V to make the experiments fair.
- Use the same apparatus (variable resistor, ammeter, volt meter) to make the experiments fair.
Dependent variables:
- Resistance - We will measure by using the volt meter and ammeter. We will use the Ohm’s Law (Voltage = Current * Resistance)with a calculator to find the resistance.
Middle
Testing a copper wire with diameter of 3rd experiment
Diameter ( mm)
Ammeter (amp)
Voltage (V)
Resistance (Ohm)
4.7
0.28
0.05957447
4.75
0.28
0.05894737
4.8
0.3
0.0625
Average resistance of the 3 Wires with Different Thickness (Diameter)
Diameter (mm) | Resistance (Ohm) |
0.06174412 | |
0.059712123 | |
0.05657483 |
Difference
mm – mm =0.002031997
mm – mm =0.003137293
Average difference = 0.002584645
Lengths
Testing Copper wire with length of 1st experiment
Lengths (cm)
Ammeter (amp)
Voltage (V)
Resistance (Ohm)
10 cm
4.6
0.3
0.06521739
15 cm
4.65
0.32
0.0688172
20 cm
4.55
0.32
0.07032967
Testing Copper wire with length of 2nd experiment
Lengths (cm)
Ammeter (amp)
Voltage (V)
Resistance (Ohm)
10 cm
4.7
0.3
0.06382979
15 cm
4.7
0.3
0.06382979
20 cm
4.65
0.32
0.0688172
Testing Copper wire with length of 3rd
Conclusion
This student written piece of work is one of many that can be found in our International Baccalaureate Physics section.
Found what you're looking for?
- Start learning 29% faster today
- 150,000+ documents available
- Just £6.99 a month