A rigid horizontal slab is attached to two identical copper rods. There is a gap, A = 0.18 mm between the middle bar, which is made of aluminium and the slab. Neglecting the mass of slab, calculate the stress in each rod when temperature of the whole assembly is increased by 85°C and choose the correct options. Use the following data: A(mm) arC) E(GPa) Each copper rod 16.8 x 10 500 120 Aluminium rod 23.1 x 10* 400 70 750 mm A Finally, copper will be under tension. Correct Option B Both copper and aluminium will be free i.e. without any stress. C Stress in copper will be 6.69 MPa (Magnitude wise) Correct Option D Stress in aluminium will be 16.7 MPa (Magnitude wise) Correct Option