51) Which one of the point given below lies in the 3rd quadrant of a Cartesian plane?

52) The number of atoms in the molecules of an element is called its

53) Fine solid powders are accelerated in a supersonic gas jet to impact with the substrate and undergo plastic deformation and adhere to the surface. This coating method is known as

54) Which is not a Nobel gas

55) The method used for determining the thickness of metallic coating by electro-chemical stripping is known as