QUES: The most common symptom of LED (and diode laser) failure is the gradual lowering of light output and loss of efficiency. Sudden failures, although rare, can also occur. Early red LEDs were notable for their short service life. With the development of high-power LEDs the devices are subjected to higher junction temperatures and higher current densities than traditional devices. This causes stress on the material and may cause early light-output degradation. To quantitatively classify useful lifetime in a standardized manner it has been suggested to use L70 or L50, which are the runtimes (typically given in thousands of hours) at which a given LED reaches 70% and 50% of initial light output, respectively.

What is a classification used in LED lighting to describe how much usefulness it will receive?
What is the answer?
ANS: L70 or L50
QUES: Typologically, Estonian represents a transitional form from an agglutinating language to a fusional language. The canonical word order is SVO (subject–verb–object).

What sort of form is Estonian transitioning into?
What is the answer?
ANS: a fusional language
QUES: Writings in Estonian became significant only in the 19th century with the spread of the ideas of the Age of Enlightenment, during the Estophile Enlightenment Period (1750–1840). Although Baltic Germans at large regarded the future of Estonians as being a fusion with themselves, the Estophile educated class admired the ancient culture of the Estonians and their era of freedom before the conquests by Danes and Germans in the 13th century.

 What Age's ideas did not allow Estonian writings to gain significance?
What is the answer?
ANS:
unanswerable