QUES: Bell's own home used a primitive form of air conditioning, in which fans blew currents of air across great blocks of ice. He also anticipated modern concerns with fuel shortages and industrial pollution. Methane gas, he reasoned, could be produced from the waste of farms and factories. At his Canadian estate in Nova Scotia, he experimented with composting toilets and devices to capture water from the atmosphere. In a magazine interview published shortly before his death, he reflected on the possibility of using solar panels to heat houses.
What kind of toilet did Bell work on?

ANS: composting

QUES: Alaska's internet and other data transport systems are provided largely through the two major telecommunications companies: GCI and Alaska Communications. GCI owns and operates what it calls the Alaska United Fiber Optic system and as of late 2011 Alaska Communications advertised that it has "two fiber optic paths to the lower 48 and two more across Alaska. In January 2011, it was reported that a $1 billion project to run connect Asia and rural Alaska was being planned, aided in part by $350 million in stimulus from the federal government.
How much money did the federal government contribute via stimulus to the non-connectvitiy between Asia and Alaska?

ANS: unanswerable

QUES: The CD was planned to be the successor of the gramophone record for playing music, rather than primarily as a data storage medium. From its origins as a musical format, CDs have grown to encompass other applications. In 1983, following the CD's introduction, Immink and Braat presented the first experiments with erasable compact discs during the 73rd AES Convention. In June 1985, the computer-readable CD-ROM (read-only memory) and, in 1990, CD-Recordable were introduced, also developed by both Sony and Philips. Recordable CDs were a new alternative to tape for recording music and copying music albums without defects introduced in compression used in other digital recording methods. Other newer video formats such as DVD and Blu-ray use the same physical geometry as CD, and most DVD and Blu-ray players are backward compatible with audio CD.
Who created the DVD and Blu-ray discs?

ANS: unanswerable

QUES: A P-N junction can convert absorbed light energy into a proportional electric current. The same process is reversed here (i.e. the P-N junction emits light when electrical energy is applied to it). This phenomenon is generally called electroluminescence, which can be defined as the emission of light from a semi-conductor under the influence of an electric field. The charge carriers recombine in a forward-biased P-N junction as the electrons cross from the N-region and recombine with the holes existing in the P-region. Free electrons are in the conduction band of energy levels, while holes are in the valence energy band. Thus the energy level of the holes will be lesser than the energy levels of the electrons. Some portion of the energy must be dissipated in order to recombine the electrons and the holes. This energy is emitted in the form of heat and light.
Where are the free electrons located in the production of electroluminescence?

ANS:
the conduction band