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Step 1:

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(4.1)

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The resistance of the motor at 10° C is 50 .

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The resistance of the motor at 20.1° C is 100 .

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Find temperature coefficient at 0° C.

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Temperature coefficient at 0° C : .

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Temperature coefficient at 0° C is /C.

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Solution:

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Temperature coefficient at 0° C is /C.

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Step 1:

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(4.2)

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The resistance of the motor at 15° C is 100 .

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Temperature coefficient is 0.004/C.

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Final temperature is 65° C

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Find the increase in resistance.

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Temperature coefficient at 0° C : .

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The increase in resistance is 20 .

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Solution:

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The increase in resistance is 20 .

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Step 1:

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(4.3)

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Negative coefficient of resistance :

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The resistance of the material decreases with increase in temperature,this phenomenon is said to be negative temperature coefficient of semiconductor.

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Semiconductors and insulators have negative temperature coefficient. These are used as thermistors.

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Positive coefficient of resistance :

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The resistance of the material increases with increase in temperature,this phenomenon is said to be positive temperature coefficient of semiconductor.

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Usually all metals and their alloys have positive temperature coefficient.

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Solution:

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The difference between between Negative coefficient of resistance and positive coefficient of resistance is the resistance of the material. \ \

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