Abstract:
This experiment aims to verify Ohm's Law using a wire as a conductor. Ohm's Law states that the current passing through a conductor between two points is directly proportional to the voltage across the two points, given constant temperature. The experiment involved varying the voltage across the wire and measuring the corresponding current to validate Ohm's Law.
Introduction:
Ohm's Law, named after the German physicist Georg Simon Ohm, is a fundamental principle in electrical engineering and physics. It establishes the relationship between voltage, current, and resistance in an electrical circuit. According to Ohm's Law:
$$V = IR$$
where:
- $$V$$ is the voltage across the conductor,
- $$I$$ is the current passing through the conductor,
- $$R$$ is the resistance of the conductor.
This experiment aims to validate Ohm's Law by directly measuring the voltage and current across a wire conductor at different resistance levels.
Experiment Details:
Materials Required:
- Power supply (variable voltage)
- Wire (conductor)
- Ammeter (to measure current)
- Voltmeter (to measure voltage)
- Connecting wires
Procedure:
- Set up the circuit by connecting the power supply, ammeter, voltmeter, and wire in series.
- Ensure all connections are secure and there are no loose ends.
- Gradually increase the voltage from the power supply while recording the corresponding current readings from the ammeter.
- Repeat step 3 for different voltage levels to obtain a range of current readings.
- Calculate the resistance of the wire using Ohm's Law formula: $$R = \frac{V}{I}$$
Observations and Calculations:
Sample observations:
| Voltage (V) | Current (I) |
|---|---|
| 2 | 0.5 |
| 4 | 1 |
| 6 | 1.5 |
Using Ohm's Law, calculate resistance:
- At 2V: $$R = \frac{2}{0.5} = 4 \Omega$$
- At 4V: $$R = \frac{4}{1} = 4 \Omega$$
- At 6V: $$R = \frac{6}{1.5} = 4 \Omega$$
Conclusion:
The experiment demonstrates that the relationship between voltage and current in a conductor is linear, confirming Ohm's Law. The resistance of the wire remains constant regardless of the applied voltage, indicating that the conductor obeys Ohm's Law. This validates the fundamental principle of electrical circuits, which is crucial in understanding and analyzing electrical systems.
Precautions:
- Ensure all connections are tight to avoid any loose connections.
- Avoid excessive voltage to prevent overheating of the wire.
- Handle equipment with care to prevent accidents or damage.
Short Questions:
- What is Ohm's Law?
- Who formulated Ohm's Law?
- What are the units of voltage, current, and resistance?
- What is the significance of Ohm's Law in electrical engineering?
- Under what conditions does Ohm's Law hold true?
- Define resistance.
- What is the formula for calculating resistance using Ohm's Law?
- Explain the concept of electrical conductivity.
- What happens to resistance when the cross-sectional area of a conductor increases?
- How does temperature affect the resistance of a conductor?
- What is a conductor?
- Give an example of a good conductor.
- What is an insulator?
- Provide an example of an insulator.
- Explain the difference between resistance and resistivity.
- What is the SI unit of resistance?
- State the relationship between resistance, length, and cross-sectional area of a conductor.
- Explain the term 'electric current'.
- What is the difference between AC (alternating current) and DC (direct current)?
- Describe the behavior of an ideal ohmic conductor.
Answer: Ohm's Law states that the current through a conductor between two points is directly proportional to the voltage across the two points.
Answer: Ohm's Law was formulated by the German physicist Georg Simon Ohm.
Answer: Voltage is measured in volts (V), current in amperes (A), and resistance in ohms ($$\Omega$$).
Answer: Ohm's Law is fundamental in understanding and analyzing electrical circuits and systems. It helps in predicting and controlling the behavior of electrical components.
Answer: Ohm's Law holds true for conductors at constant temperature and within their linear range of operation.
Answer: Resistance is the measure of opposition to the flow of electric current in a conductor.
Answer: $$R = \frac{V}{I}$$, where $$R$$ is resistance, $$V$$ is voltage, and $$I$$ is current.
Answer: Electrical conductivity is a measure of a material's ability to conduct electric current. Materials with high conductivity allow electric charges to flow easily.
Answer: When the cross-sectional area of a conductor increases, its resistance decreases.
Answer: Generally, as the temperature of a conductor increases, its resistance also increases.
Answer: A conductor is a material that allows electric current to flow through it easily.
Answer: Copper is an example of a good conductor of electricity.
Answer: An insulator is a material that does not allow electric current to flow through it easily.
Answer: Rubber is an example of an insulator.
Answer: Resistance is the measure of opposition to current flow in a conductor, while resistivity is an intrinsic property of a material that quantifies its resistance to current flow.
Answer: The SI unit of resistance is the ohm ($$\Omega$$).
Answer: Resistance is directly proportional to the length of the conductor and inversely proportional to its cross-sectional area.
Answer: Electric current is the flow of electric charge through a conductor, measured in amperes (A).
Answer: AC periodically changes direction, while DC flows in one direction only.
Answer: An ideal ohmic conductor obeys Ohm's Law, maintaining a constant resistance regardless of the applied voltage.
Multiple Choice Questions (MCQs):
- What does Ohm's Law describe?
- The relationship between voltage and current
- The relationship between voltage and resistance
- The relationship between current and resistance
- All of the above
- What is the unit of resistance?
- Volts
- Amps
- Ohms
- Watts
- Who is credited with formulating Ohm's Law?
- Thomas Edison
- Nikola Tesla
- Georg Simon Ohm
- James Clerk Maxwell
- What does a straight line on a voltage-current graph indicate?
- The circuit is open
- The circuit is short-circuited
- The conductor obeys Ohm's Law
- There is no voltage across the conductor
- Which of the following is not a component of Ohm's Law?
- Voltage
- Current
- Resistance
- Power
Answer: a. The relationship between voltage and current
Answer: c. Ohms
Answer: c. Georg Simon Ohm
Answer: c. The conductor obeys Ohm's Law
Answer: d. Power