Context and question: 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.
What lightens a conventional bulb?
Answer: unanswerable
Context and question: In December 2013, Vatican officials approved a supposed miracle that was attributed to the intercession of the late pontiff which was the curing of an unborn child in California, U.S.A in the 1990s. It was expected that Pope Francis would approve the miracle in the near future, thus, warranting the beatification of the late pontiff. In February 2014, it was reported that the consulting Vatican theologians to the Congregation for the Causes of Saints recognized the miracle attributed to the late pontiff.
What is the process called that acknowledges sainthood?
Answer: beatification
Context and question: An advantage of the universal motor is that AC supplies may be used on motors which have some characteristics more common in DC motors, specifically high starting torque and very compact design if high running speeds are used. The negative aspect is the maintenance and short life problems caused by the commutator. Such motors are used in devices such as food mixers and power tools which are used only intermittently, and often have high starting-torque demands. Multiple taps on the field coil provide (imprecise) stepped speed control. Household blenders that advertise many speeds frequently combine a field coil with several taps and a diode that can be inserted in series with the motor (causing the motor to run on half-wave rectified AC). Universal motors also lend themselves to electronic speed control and, as such, are an ideal choice for devices like domestic washing machines. The motor can be used to agitate the drum (both forwards and in reverse) by switching the field winding with respect to the armature.
How is stepped speed control achieved?
Answer:
Multiple taps on the field coil provide