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More Lessons for IGCSE Physics

Math Worksheets

A series of free GCSE/IGCSE Physics Notes and Lessons.

**Resistance of a Filament Lamp**

In this lesson, we will

• Describe the current/potential difference graphs for an ohmic conductor and for a filament lamp.

• Explain the shape of this graph.

Current through a resistor is directly proportional to the potential difference. The resistance is constant. Such a resistor is called an ohmic conductor.

The current through a filament lamp is not directly proportional to the potential difference. This is because the filament gets hot, which causes the resistance to increase. At high temperatures, the atoms in the filament vibrate more. The electrons in the current now collide more with the atoms. More energy is needed to push the current through the filament. As the potential difference increases, the current no longer increases as much.

**Resistance in filament light bulbs**

Ohm's Law states that

"The current through a resistor at constant temperature is directly proportional to the potential difference across the resistor"

A filament light bulb is a non-ohmic conductor.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

More Lessons for IGCSE Physics

Math Worksheets

In this lesson, we will

• Describe the current/potential difference graphs for an ohmic conductor and for a filament lamp.

• Explain the shape of this graph.

Current through a resistor is directly proportional to the potential difference. The resistance is constant. Such a resistor is called an ohmic conductor.

The current through a filament lamp is not directly proportional to the potential difference. This is because the filament gets hot, which causes the resistance to increase. At high temperatures, the atoms in the filament vibrate more. The electrons in the current now collide more with the atoms. More energy is needed to push the current through the filament. As the potential difference increases, the current no longer increases as much.

Ohm's Law states that

"The current through a resistor at constant temperature is directly proportional to the potential difference across the resistor"

A filament light bulb is a non-ohmic conductor.

Rotate to landscape screen format on a mobile phone or small tablet to use the **Mathway** widget, a free math problem solver that **answers your questions with step-by-step explanations**.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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