QUES: The Soviet Zond spacecraft was not yet ready for piloted circumlunar missions in 1968, after five unsuccessful and partially successful automated test launches: Cosmos 146 on March 10, 1967; Cosmos 154 on April 8, 1967; Zond 1967A September 27, 1967; Zond 1967B on November 22, 1967. Zond 4 was launched on March 2, 1968, and successfully made a circumlunar flight. After its successful flight around the Moon, Zond 4 encountered problems with its Earth reentry on March 9, and was ordered destroyed by an explosive charge 15,000 meters (49,000 ft) over the Gulf of Guinea. The Soviet official announcement said that Zond 4 was an automated test flight which ended with its intentional destruction, due to its recovery trajectory positioning it over the Atlantic Ocean instead of over the USSR.
Where was the Zond 4 over when it was destroyed by an explosion?

ANS: Gulf of Guinea

QUES: The British, for their part, lacked both a unified command and a clear strategy for winning. With the use of the Royal Navy, the British were able to capture coastal cities, but control of the countryside eluded them. A British sortie from Canada in 1777 ended with the disastrous surrender of a British army at Saratoga. With the coming in 1777 of General von Steuben, the training and discipline along Prussian lines began, and the Continental Army began to evolve into a modern force. France and Spain then entered the war against Great Britain as Allies of the US, ending its naval advantage and escalating the conflict into a world war. The Netherlands later joined France, and the British were outnumbered on land and sea in a world war, as they had no major allies apart from Indian tribes.
When was the battle of Saratoga fought?

ANS: 1777

QUES: In a conventional lamp, the evaporated tungsten eventually condenses on the inner surface of the glass envelope, darkening it. For bulbs that contain a vacuum, the darkening is uniform across the entire surface of the envelope. When a filling of inert gas is used, the evaporated tungsten is carried in the thermal convection currents of the gas, depositing preferentially on the uppermost part of the envelope and blackening just that portion of the envelope. An incandescent lamp that gives 93% or less of its initial light output at 75% of its rated life is regarded as unsatisfactory, when tested according to IEC Publication 60064. Light loss is due to filament evaporation and bulb blackening. Study of the problem of bulb blackening led to the discovery of the Edison effect, thermionic emission and invention of the vacuum tube.
Where in the bulb is evaporated tungsten deposited when a vacuum is used?

ANS: across the entire surface of the envelope

QUES: Copper, silver and gold are in group 11 of the periodic table, and they share certain attributes: they have one s-orbital electron on top of a filled d-electron shell and are characterized by high ductility and electrical conductivity. The filled d-shells in these elements do not contribute much to the interatomic interactions, which are dominated by the s-electrons through metallic bonds. Unlike metals with incomplete d-shells, metallic bonds in copper are lacking a covalent character and are relatively weak. This explains the low hardness and high ductility of single crystals of copper. At the macroscopic scale, introduction of extended defects to the crystal lattice, such as grain boundaries, hinders flow of the material under applied stress, thereby increasing its hardness. For this reason, copper is usually supplied in a fine-grained polycrystalline form, which has greater strength than monocrystalline forms.
How is copper normally supplied?

ANS:
fine-grained polycrystalline form