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| Resistance is extensive, resistivity is _____. |
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| The property that describes the ease of charge carrier migration in response to an external electric field. |
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Term
| A material with a partially filled valence band |
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Definition
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| Average charge carrier velocity divided by the electric field strength. |
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Definition
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Term
| The impurity level within the band gap of a semiconductor associated with holes |
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Definition
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Term
| An extrinsic semiconductor in which holes are the dominant charge carriers |
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Definition
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| An instrinsic semiconductor in which electrons are the dominant charge carriers |
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Definition
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Term
| For a semiconductor, increasing the temperature _____ the mobility of the holes and electrons. |
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| For a metal, increasing the temperature _____ the mobility of the holes and electrons. |
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Term
| Adding copper to aluminum will _______ the electrical conductivity of aluminum. |
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Definition
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Term
| Why are both Na and MG conductors even though Mg has a FULL valence band? |
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Definition
| They both have no band gap. |
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Term
| Explain why no hole is generated by the electron excitation involving a donor impurity atom. |
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Definition
| Since it is an extra electron, no hole is created; the electron is just free to move. |
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Term
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Definition
| An impurity substance that is inserted into a substance (in very low concentrations) to alter the electrical properties of the substance. |
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Term
| Why is conductivity decrease in a metal as temperature increases? |
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Definition
| The band gap in the metal is small and thus the electrons can easily take a leap to conduction band and conduct electricity but with increase in temperature, the thermal motion makes the electrons to collide and disturb the free flow. Thus, conductivity is decreased. However, with decrease in temperature, the thermal effect is nullified and the electrons can flow smoothly without hindrance and thus conductivity increases. |
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Term
| Why is conductivity increase in a semiconductor as temperature increases? |
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Definition
| In semi conductors, the band gap is big but small enough for few electrons to take a leap to the conduction band and conduct electricity to some extent. However with increase in temperature they get charged with thermal energy which is sufficient to overcome the energy barrier and leap to the conduction band and thus, their conductivity increases. |
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