Resistance

Resistance (R) = Voltage (V) / Current (I)
R = 12 V / 2 A
R = 6 Ω

Explanation: The formula R=V/I is used to calculate resistance from voltage and current.

According to Ohm's Law (V=IR), the potential difference is directly proportional to the current, assuming the resistance remains constant. This means if you double the potential difference, the current will also double, and vice-versa.

Resistance, R = Voltage, V / Current, I
R = 6.0 V / 0.50 A
R = 12 Ω

The resistance is calculated using Ohm's Law. Voltage is divided by current to find the resistance.

1. Connect the resistor in a circuit with a power supply, an ammeter (in series), and a voltmeter (in parallel across the resistor).
2. Adjust the power supply to provide a suitable voltage and record the voltage (V) from the voltmeter and the current (I) from the ammeter.
3. Calculate the resistance (R) using Ohm's Law: R = V/I.

The resistance of a metallic wire is directly proportional to its length. This means that if the length of the wire increases, the resistance increases proportionally, assuming all other factors remain constant.

The resistance of a metallic wire is inversely proportional to its cross-sectional area. This means that as the cross-sectional area increases, the resistance decreases, and vice versa, assuming all other factors remain constant. A larger area provides more space for electrons to flow, reducing opposition.

Sketch should show a curve, starting with a steep slope near the origin, then flattening out at higher voltages/currents.

Explanation: At higher voltages, the filament lamp gets hotter. The increased temperature causes the resistance of the filament to increase. Since resistance = voltage / current (R = V/I), for the same increase in voltage, the increase in current becomes smaller. This results in a less steep slope on the I-V graph at higher voltages.

The I-V graph for a diode shows very little current flowing when the voltage is negative (reverse bias). At a specific positive voltage (forward voltage), the current increases rapidly.

Resistance is directly proportional to length.

R₁/L₁ = R₂/L₂

2.0 / 5.0 = R₂ / 15.0

R₂ = (2.0 / 5.0) * 15.0

R₂ = 6.0 Ω

Answer: 6.0 Ω

Increasing the cross-sectional area provides more space for electrons to flow. With more available space, electrons experience fewer collisions with atoms in the wire. Fewer collisions mean less opposition to the current, hence a lower resistance.

(Area ∝ 1/Resistance)