QUES: The phase of reflection of electromagnetic waves depends on the polarization of the incident wave. Given the larger refractive index of the ground (typically n=2) compared to air (n=1), the phase of horizontally polarized radiation is reversed upon reflection (a phase shift of  radians or 180°). On the other hand, the vertical component of the wave's electric field is reflected at grazing angles of incidence approximately in phase. These phase shifts apply as well to a ground modelled as a good electrical conductor.
Besides a ground, what has these phases apply well to?

ANS: electrical conductor

QUES: The polyphony of Christian a cappella music began to develop in Europe around the late 15th century, with compositions by Josquin des Prez. The early a cappella polyphonies may have had an accompanying instrument, although this instrument would merely double the singers' parts and was not independent. By the 16th century, a cappella polyphony had further developed, but gradually, the cantata began to take the place of a cappella forms. 16th century a cappella polyphony, nonetheless, continued to influence church composers throughout this period and to the present day. Recent evidence has shown that some of the early pieces by Palestrina, such as what was written for the Sistine Chapel was intended to be accompanied by an organ "doubling" some or all of the voices. Such is seen in the life of Palestrina becoming a major influence on Bach, most notably in the aforementioned Mass in B Minor. Other composers that utilized the a cappella style, if only for the occasional piece, were Claudio Monteverdi and his masterpiece, Lagrime d'amante al sepolcro dell'amata (A lover's tears at his beloved's grave), which was composed in 1610, and Andrea Gabrieli when upon his death it was discovered many choral pieces, one of which was in the unaccompanied style. Learning from the preceding two composeres, Heinrich Schütz utilized the a cappella style in numerous pieces, chief among these were the pieces in the oratorio style, which were traditionally performed during the Easter week and dealt with the religious subject matter of that week, such as Christ's suffering and the Passion. Five of Schutz's Historien were Easter pieces, and of these the latter three, which dealt with the passion from three different viewpoints, those of Matthew, Luke and John, were all done a cappella style. This was a near requirement for this type of piece, and the parts of the crowd were sung while the solo parts which were the quoted parts from either Christ or the authors were performed in a plainchant.
How were the pieces written by Josquin des Prez performed during Easter week?

ANS: unanswerable

QUES: During World War II, Imperial Japan invaded most of the former western colonies. The Shōwa occupation regime committed violent actions against civilians such as the Manila massacre and the implementation of a system of forced labour, such as the one involving 4 to 10 million romusha in Indonesia. A later UN report stated that four million people died in Indonesia as a result of famine and forced labour during the Japanese occupation. The Allied powers who defeated Japan in the South-East Asian theatre of World War II then contended with nationalists to whom the occupation authorities had granted independence.
Who reported that 4  thousand people died do to famine and forced labour?

ANS: unanswerable

QUES: Life expectancy at birth is estimated to be 52.2 years in 2012 – among the lowest in the world. The AIDS epidemic is a large problem in Namibia. Though its rate of infection is substantially lower than that of its eastern neighbour, Botswana, approximately 13.1% of the adult population is[update] infected with HIV. In 2001, there were an estimated 210,000 people living with HIV/AIDS, and the estimated death toll in 2003 was 16,000. According to the 2011 UNAIDS Report, the epidemic in Namibia "appears to be leveling off." As the HIV/AIDS epidemic has reduced the working-aged population, the number of orphans has increased. It falls to the government to provide education, food, shelter and clothing for these orphans.
What is the age expectancy in Botswana as of 2012?

ANS:
unanswerable