WJEC Physics for AS Level: Revision Workbook

(i) Aled measured the diameter of the wire to be 0.20 mm, and its effective length to be 2.500 m. Suggest how he obtained this value for the diameter and give a reason for your answer. 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(ii) Use the graph and the values given in (b)(i) to obtain a value for the Young modulus of brass. Give your answer to an appropriate number of significant figures. 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(iii) Aled believed that for the two largest masses used the wire was stretching inelastically . (I) Suggest how he could have confirmed that inelastic stretching had occurred. 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(II) Explain briefly, on an atomic level, how a metal deforms inelastically. 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(c) In the 1950s, physicists confirmed that it was the movement of dislocations that allowed inelastic deformation of metals to take place at relatively low stresses. Suggest how we have benefitted practically from the application of this knowledge. 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Unit 1 Practice paper | 161 Unit 1 Practice paper