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InterviewSolution
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The pressure that has to be applied to the ends of a steel wire of length 10 cm to keep its length constant when its temperature is raised by 100°C is (For steel, Young's modulus is 2 x 1011 Nm-2 and coefficient If thermal expansion is 1.1 x 10-5 K-1)(a) 2.2 x 108Pa (b) 2.2 x 109Pa (c) 2.2 x 107Pa (d) 2.2 x 106Pa |
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Answer» The correct option is (a) 2.2 x 108 Pa Explanation: We have change in length due to the change in temperature (considering no obstruction) ΔL= αLΔT or ΔL= 1.1 x 10-5 x 0.10 x 100 = 1.1 x 10-4 m Now pressure which needs to be applied would be given using F/A = Pressure = (ΔL x Y)/L = (1.1 x 10-4 x 2 x 1011)/0.1 (Here ΔL is the expansion prevented) = 2.2 x 108 Pa |
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