Qstnid -Iv-1-a-the Stress (B) The Strain And (C) The Elongation. Young Modulus Of The Metal Is 2.0 &Times; 10<sup>11</sup> N M<sup>-2</sup>. (B) The Strain And (C) The Elongation. Young Modulus Of The Metal Is 2.0 &Times; 10<sup>11</sup> N M<sup>-2</sup>. - 14: Some Mechanical Properties Of Matter - Neet-xii-physics

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NEET-XII-Physics

14: Some Mechanical Properties of Matter

with Solutions - page 5

Qstn# iv-1-a Prvs-Qstn Next-Qstn

#1-a
the stress (b) the strain and (c) the elongation. Young modulus of the metal is 2.0 × 10¹¹ N m^-2. (b) the strain and (c) the elongation. Young modulus of the metal is 2.0 × 10¹¹ N m^-2.
Ans : Stress = F/A
F = mg
= `` 10\times 10`` = 100 N (g = 10 m/s²)
`` \therefore \frac{F}{A}=\frac{100}{4\times {10}^{-6}}``
`` =2.5\times {10}^{7}\,\mathrm{\,N\,}/{\,\mathrm{\,m\,}}^{2}`` (b) Strain = `` \frac{\Delta L}{L}``

Or, `` \,\mathrm{\,Strain\,}=\frac{\,\mathrm{\,Stress\,}}{Y}``
`` \,\mathrm{\,Strain\,}=\frac{2.5\times {10}^{7}}{2\times {10}^{11}}``
`` =1.25\times {10}^{-4}\,\mathrm{\,N\,}/{\,\mathrm{\,m\,}}^{2}`` (c) Let the elongation in the wire be `` ∆L``.
`` \,\mathrm{\,Strain\,}=\frac{\Delta L}{L}``
`` \Rightarrow \,\mathrm{\,\Delta \,}L=\left(\,\mathrm{\,Strain\,}\right)\times L``
`` =1.25\times {10}^{-4}\times 3``
`` =3.75\times {10}^{-4}\,\mathrm{\,m\,}``
Page No 300: (b) Strain = `` \frac{\Delta L}{L}``

Or, `` \,\mathrm{\,Strain\,}=\frac{\,\mathrm{\,Stress\,}}{Y}``
`` \,\mathrm{\,Strain\,}=\frac{2.5\times {10}^{7}}{2\times {10}^{11}}``
`` =1.25\times {10}^{-4}\,\mathrm{\,N\,}/{\,\mathrm{\,m\,}}^{2}`` (c) Let the elongation in the wire be `` ∆L``.
`` \,\mathrm{\,Strain\,}=\frac{\Delta L}{L}``
`` \Rightarrow \,\mathrm{\,\Delta \,}L=\left(\,\mathrm{\,Strain\,}\right)\times L``
`` =1.25\times {10}^{-4}\times 3``
`` =3.75\times {10}^{-4}\,\mathrm{\,m\,}``
Page No 300:

#1-b
the strain and
Ans : Strain = `` \frac{\Delta L}{L}``

Or, `` \,\mathrm{\,Strain\,}=\frac{\,\mathrm{\,Stress\,}}{Y}``
`` \,\mathrm{\,Strain\,}=\frac{2.5\times {10}^{7}}{2\times {10}^{11}}``
`` =1.25\times {10}^{-4}\,\mathrm{\,N\,}/{\,\mathrm{\,m\,}}^{2}``

#1-c
the elongation. Young modulus of the metal is 2.0 × 10¹¹ N m^-2.
Ans : Let the elongation in the wire be `` ∆L``.
`` \,\mathrm{\,Strain\,}=\frac{\Delta L}{L}``
`` \Rightarrow \,\mathrm{\,\Delta \,}L=\left(\,\mathrm{\,Strain\,}\right)\times L``
`` =1.25\times {10}^{-4}\times 3``
`` =3.75\times {10}^{-4}\,\mathrm{\,m\,}``
Page No 300: