Q. 24 The process of reheating the martensitic steel to reduce its brittleness without any significant loss in its hardness is (A) normalising (C) quenching (B) annealing (D) tempering Q.25 In solid-state welding, the contamination layers between the surfaces to be welded are removed by (A) alcohol (C) water jet (B) plastic deformation (D) sand blasting Q. 33 Consider a cantilever beam, having negligible mass and uniform flexural rigidity, with length 0.01 m. The frequency of vibration of the beam, with a 0.5 kg mass attached at the free tip, is 100 Hz. The flexural rigidity (in N.m) of the beam is