This shows the $I-V$ Characteristic of an electrical component.

Calculate the resistance of the component when the potential difference across it is  $2.0V$.

 

This shows the $I-V$ Characteristic of an electrical component

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Calculate the resistance of the component when the potential difference across it is $5.0V.$

This shows the $1-V$ characteristic of an electrical component

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Suggest what the component is.

A student connects a thermistor to a battery and an ammeter. He places the thermistor in a beaker of water and gradually heats the water from $10°\text{C}$ to its boiling point, recording the value of the current as he does so. He then plots a graph of the current in the thermistor against the temperature of the water

(a) Sketch the graph you would expect the student to obtain from the experiment

A student connects a NTC thermistor to a battery and an ammeter. He places the thermistor in a beaker of water and gradually heats the water from 10 oc to its boiling point, recording the value of the current as he does so. He then plots a graph of the current in the thermistor against the temperature of the water Explain how the student could now use the thermistor as a thermometer. 

 Describe the difference between the conduction processes in copper and in silicon, a semiconductor.

Explain why the resistance of a metallic conductor increases with temperature while that of a semiconductor decreases.

A nichrome wire has a length of $1.5m$ and a cross-sectional area of$0.0080m{m}^2.$. The resistivity of nichrome is $1.30\times {10}^{-8}nm.$

Calculate the resistance of the wire.

A nichrome wire has a length of $1.5m$ and a cross-sectional area of$0.0080m{m}^2.$. The resistivity of nichrome is $1.30\times {10}^{-8}nm.$ Calculate the length of this wire that would be needed to make an element of an electric heater of resistance $30\Omega .$