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| Linear Expansion |
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| Let the length of the rod increase to 'l2'. |
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Increase in length = (l2-l1) =  l |
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Rise in temperature = (t2-t1)0c =  t. |
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| The ratio of increase in length to its original length per every degree rise in temperature is known as 'the coefficient of linear expansion'. |
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| The coefficient of linear expansion is denoted by the letter 'a' . |
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| Where l = original length |
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| The coefficient of linear expansion is a characteristic property of the material of the rod. |
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| This means that if rods of same length and at same temperature, but made of different materials are heated to attain the same higher temperature then, increase in their lengths will not be the same but will be different. |
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| Coefficient of linear expansions of certain materials are given below |
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| 'a' of iron is 12x10-6/0C means, if a rod of length 1m is heated through 10C, then length increases by an amount of 12x10-6 m. |
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