Q14 of 64 Page 12

Two-metre scales, one of steel and the other of aluminium-centimetre/steel-centimetre at (a) 0°C, (b) 40°C and (c) 100°C. α for steel = and for aluminium *

a) b) c)

Explanation:


Given,


Coefficient of linear expansionof AluminiumαAl, is2.3 ×10-5°C-1


Coefficient of linear expansion of steel, αS, is 1.1 ×10-5°C-1


The scale is calibrated at the reference temperature of 20°C


Formula used


L0= Length at a reference temperature,


α= coefficient of linear expansion,


θ= Change in temperature.


‘Al’ and ‘S’ will be used as subscripts to denote Aluminium and Steel respectively.


a) at 0°C




b) at 40°C



c) at 100°C



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