With the aid of a diagram, show how atoms are packed on a face centred cubic lattice. identify the close-packed planes and state their miller indices. [3 marks] (b) the unit cell dimension of face-centred cubic copper is 0.36 nm. calculate the longest wavelength of x-rays that will produce diffraction from the close-packed planes. [3 marks] (c) an incoming x-ray beam given by 3.49x10 (3i +2k)m" is incident on a copper sample. write down the corresponding wave vector for an outgoing beam, diffracted by the close- packed plane from part (a). [4 marks] (d) stating any assumptions that you use, what is the radius of a copper atom? [2 marks] (e) explain why there is no diffraction from x-rays of 0.6 nm. [4 marks] (f) would you expect to see diffraction from nacl (unit cell lattice constant 0.56 nm) using x-rays of wavelength 0.8 nm?

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

bacteria that live on the ocean floor are sustained by phytoplankton. phytoplankton, microscopic marine photosynthetic organisms, have a vastly significant role to play not only in the marine food web of which they’re part of, but also on a more global scale. despite their infinitely small size in comparison to other marine organisms, these tiny creatures occupy an immensely important ecological niche: they are the foundation of the marine food web, and as primary producers, play key roles in supporting all other organisms in the marine environment, as well as in the regulation of the earth’s climate through the sequestration of carbon, oxygen production, and other related processes. phytoplankton account for roughly half of all global primary productivity; therefore, their significance extends far beyond the marine environment alone. there is an intriguing sense of irony in the realization that these tiny living beings that often live out their existence unnoticed and undetected by the rest of the world, have such a far-reaching impact on the lives of virtually all other living organisms on the planet, particularly on those in the marine environment. the world that we have become accustomed to has been and is continuously shaped by the workings of these miniscule yet vital “plants of the sea”.

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