A composite bar made up of steel and copper bars of equal lengths are heated through 100°C. The stresses developed shall be

Answer: Option B

When a composite bar made up of different materials, such as steel and copper, is heated, it experiences thermal expansion. Since steel has a higher coefficient of thermal expansion compared to copper, the following stress distribution occurs:

Steel (outer material) expands more and tends to elongate, resulting in tensile stress. Copper (inner material) expands less and tends to contract, resulting in compressive stress.

So, in a composite bar made up of steel and copper bars of equal lengths heated through 100°C, the stresses developed shall be tensile in steel and compressive in copper. This is represented by Option B.