The practical involves measuring current and voltage across different resistors to calculate resistance using Ohm's Law.

1. Setup: You'll connect a circuit with a resistor (let's call it R₁), an ammeter to measure current (I₁), and a voltmeter to measure voltage (V₁) across R₁.
2. Data Collection: You'll take five sets of readings. For each set, you'll adjust the power supply to increase the current (I₁) flowing through R₁ and record the corresponding voltage (V₁) across it.
3. Calculation: For each set of readings, you'll calculate the resistance R₁ using the formula: R₁ = V₁ / I₁ (in Ohms, Ω)
4. Tabulation: Record all your I₁, V₁, and calculated R₁ values in the first table provided.

1. Setup: You'll connect a different circuit (as shown in Fig. 3.2, which isn't provided, but implies a different resistor or a combination of resistors). Let's call the resistance of this setup R₂. You'll use an ammeter to measure current (I₂) and a voltmeter to measure voltage (V₂) across R₂.
2. Data Collection: Similar to Part 1, you'll take multiple readings, increasing the current (I₂) and recording the corresponding voltage (V₂).
3. Calculation: For each set of readings, you'll calculate the resistance R₂ using the formula: R₂ = V₂ / I₂ (in Ohms, Ω)
4. Tabulation: Record all your I₂, V₂, and calculated R₂ values in the second table provided.

Now let's look at the questions:

You need to plot two graphs on the same graph page:

1. Graph 1: Plot the voltage V₁ (y-axis) against the current I₁ (x-axis) using the data from Part 1.
2. Graph 2: Plot the voltage V₂ (y-axis) against the current I₂ (x-axis) using the data from Part 2. Both graphs should ideally be straight lines passing through the origin, demonstrating Ohm's Law.

You need to find the value of a resistor (let's call it Rₓ) that, when connected in parallel with a 2 Ω resistor, results in an effective resistance (R_eff) of 1.5 Ω.

Here are four precautions you could take:

• Ensure all connections are tight and clean to minimize contact resistance.
• Read the ammeter and voltmeter scales perpendicularly to avoid parallax error.
• Use a rheostat or variable power supply to gradually change the current and voltage, taking readings at regular intervals.
• Allow the circuit to cool down between readings or after prolonged use, as resistance can change with temperature.