11. Calculate the 20 diffraction angle for the (311) plane in platinum. The incident x-ray beam has a wavelength of 0.1542 nm. (You will need to find the lattice constant from an online source such as Wikipedia.)

Aluminium has a density of 2.7 g/cm3.Suppose you would like to  produce a composite material based on aluminium density of 1.5 g/cm3.Design a material that would have this density.would introducing beads of polyethylene ,with  a density of 0.95 g/cm3 ,into the aluminium be likely possibility ?Explain.

Describe the electron configuration of a sodium atom and explain how it determines its chemical properties.

Pick a statement which incorrectly describes steel ? A. It contains carbon atoms in the holes of its iron crystals. B. The presence of carbon-iron bonds in the alloy make steel harder and stronger than pure iron. C. Pure iron is relatively soft and ductile because it lacks directional bonding. O D. The amount of carbon directly affects the properties of steel. O E. All of these are true.