Yc×(ΔLc/Lc)=Ys×(ΔLs/Ls) ⇒1×1011×(11×10−3)=2×1011×(0.5ΔLs) ∴ΔLs=20.5×10−3=0.25 mm Therefore, total extension of the composite wire =ΔLc+ΔLs=1 mm+0.25 m=1.25 m
JEE Main 2013 — Physics Mechanics
A copper wire of length 1.0 m and a steel wire of length 0.5 m having equal cross-sectional areas are joined end to end. The composite wire is stretched by a certain load which stretches the copper wire by 1 mm. If the Young's modulii of copper and steel are respectively 1.0×1011 Nm−2 and 2.0×1011Nm−2, the total extension of the composite wire is :
Held on 23 Apr 2013 · Verified 6 Jul 2026.
1.75 mm
2.0 mm
1.50 mm
1.25 mm
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