Analyze IV characteristic graphs for a metallic conductor, an incandescent bulb, and a thermistor to determine ohmic and non-ohmic behavior.

Analysis of IV Characteristic Graphs for Different Conductors

The I-V characteristic graph represents the relationship between the current (I) and voltage ($V$) for different electrical components. The nature of this graph helps determine whether a material exhibits Ohmic or Non-Ohmic behavior.

 1. Metallic Conductor (Ohmic Behavior)

• Graph Shape: A straight line passing through the origin.
• Explanation:
  • A metallic conductor (e.g., copper, silver) obeys Ohm’s Law: V=IR.
  • The resistance (R) remains constant as voltage increases.
  • The slope (VI) represents resistance.
• Conclusion: Ohmic Conductor
  • Example: Copper wire, resistors.

2. Incandescent Bulb (Non-Ohmic Behavior)

• Graph Shape: A curved graph that flattens at higher voltages.
• Explanation:
  • At low voltage, the filament’s temperature is low, and resistance is nearly constant.
  • As voltage increases, the filament heats up, increasing resistance.
  • Since $R$ increases with temperature, the current grows at a decreasing rate.
• Conclusion: Non-Ohmic Conductor
  • Example: Tungsten filament bulb.

3. Thermistor (Non-Ohmic Behavior)

• Graph Shape:
  • NTC (Negative Temperature Coefficient) Thermistor: A downward curve, showing increased current at higher voltage.
  • PTC (Positive Temperature Coefficient) Thermistor: An upward curve, showing decreased current at higher voltage.
• Explanation:
  • NTC Thermistor: As temperature rises, resistance decreases, allowing more current to flow.
  • PTC Thermistor: As temperature rises, resistance increases, limiting current flow.
• Conclusion: Non-Ohmic Conductor
  • Example: Temperature sensors, circuit protection devices.

Summary

Thus, metallic conductors are ohmic, while incandescent bulbs and thermistors are non-ohmic due to temperature-dependent resistance.