Question: Read this and answer the question

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.

What is the phenomenon where a P-N junction emits light when an electrical current is applied to it?
Answer: electroluminescence
Question: Read this and answer the question

The Egyptians begrudgingly accepted the Ptolemies as the successors to the pharaohs of independent Egypt, though the kingdom went through several native revolts. The Ptolemies took on the traditions of the Egyptian Pharaohs, such as marrying their siblings (Ptolemy II was the first to adopt this custom), having themselves portrayed on public monuments in Egyptian style and dress, and participating in Egyptian religious life. The Ptolemaic ruler cult portrayed the Ptolemies as gods, and temples to the Ptolemies were erected throughout the kingdom. Ptolemy I even created a new god, Serapis, who was combination of two Egyptian gods: Apis and Osiris, with attributes of Greek gods. Ptolemaic administration was, like the Ancient Egyptian bureaucracy, highly centralized and focused on squeezing as much revenue out of the population as possible though tariffs, excise duties, fines, taxes and so forth. A whole class of petty officials, tax farmers, clerks and overseers made this possible. The Egyptian countryside was directly administered by this royal bureaucracy. External possessions such as Cyprus and Cyrene were run by strategoi, military commanders appointed by the crown.

Apis and Osiris combined to make which god?
Answer: Serapis
Question: Read this and answer the question

Once Pan had the audacity to compare his music with that of Apollo, and to challenge Apollo, the god of the kithara, to a trial of skill. Tmolus, the mountain-god, was chosen to umpire. Pan blew on his pipes, and with his rustic melody gave great satisfaction to himself and his faithful follower, Midas, who happened to be present. Then Apollo struck the strings of his lyre. Tmolus at once awarded the victory to Apollo, and all but Midas agreed with the judgment. He dissented and questioned the justice of the award. Apollo would not suffer such a depraved pair of ears any longer, and caused them to become the ears of a donkey.

Who was chosen as umpire of the trial of skill?
Answer:
Tmolus