A brass rod of cross-sectional area \[1\,c{{m}^{2}}\] and length 0.2 m is compressed lengthwise by a weight of 5 kg. If Young's modulus of elasticity of brass is \[1\times {{10}^{11}}\,N/{{m}^{2}}\] and \[g=10\,m/{{\sec }^{2}}\], then increase in the energy of the rod will be [MP PMT 1991]

• A. \[{{10}^{-5}}\]J
• B. \[2.5\times {{10}^{-5}}\]J
• C. \[5\times {{10}^{-5}}\]J
• D. \[2.5\times {{10}^{-4}}\]J