Two bars, one of steel and the other of copper having areas of cross-sections As and Ac, coefficient of expansion s and c and Young's Modulii Es and Es are rigidly connected together at the ends and subjected to temperature change of t . If the length of the bars initially is L, the final extension of the two bars at t temperature is given by

• A. <img src="/_files/images/civil-engineering/theory-of-structures/82-21-15-1.png">
• B. <img src="/_files/images/civil-engineering/theory-of-structures/82-21-15-2.png">
• C. <img src="/_files/images/civil-engineering/theory-of-structures/82-21-15-3.png">
• D. <img src="/_files/images/civil-engineering/theory-of-structures/82-21-15-4.png">