Problem: Transistor:

In a grounded-emitter transistor circuit, such as the light-switch circuit shown, as the base voltage rises, the emitter and collector currents rise exponentially. The collector voltage drops because of reduced resistance from collector to emitter. If the voltage difference between the collector and emitter were zero (or near zero), the collector current would be limited only by the load resistance (light bulb) and the supply voltage. This is called saturation because current is flowing from collector to emitter freely. When saturated, the switch is said to be on.

What causes reduced resistance from collector to emitter?
---
A: unanswerable


Problem: For many centuries, wealthy and powerful members of the szlachta sought to gain legal privileges over their peers. Few szlachta were wealthy enough to be known as magnates (karmazyni—the "Crimsons", from the crimson colour of their boots). A proper magnate should be able to trace noble ancestors back for many generations and own at least 20 villages or estates. He should also hold a major office in the Commonwealth.
A proper magnates own what?
---
Answer: own at least 20 villages or estates.


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The basic annelid form consists of multiple segments. Each segment has the same sets of organs and, in most polychaetes, has a pair of parapodia that many species use for locomotion. Septa separate the segments of many species, but are poorly defined or absent in others, and Echiura and Sipuncula show no obvious signs of segmentation. In species with well-developed septa, the blood circulates entirely within blood vessels, and the vessels in segments near the front ends of these species are often built up with muscles that act as hearts. The septa of such species also enable them to change the shapes of individual segments, which facilitates movement by peristalsis ("ripples" that pass along the body) or by undulations that improve the effectiveness of the parapodia. In species with incomplete septa or none, the blood circulates through the main body cavity without any kind of pump, and there is a wide range of locomotory techniques – some burrowing species turn their pharynges inside out to drag themselves through the sediment.
What movement method do some extinct annelids use?
A: unanswerable


Context and question: As the election approached, other prominent citizens and politicians from both parties urged Eisenhower to run for president. In January 1948, after learning of plans in New Hampshire to elect delegates supporting him for the forthcoming Republican National Convention, Eisenhower stated through the Army that he was "not available for and could not accept nomination to high political office"; "life-long professional soldiers", he wrote, "in the absence of some obvious and overriding reason, [should] abstain from seeking high political office". Eisenhower maintained no political party affiliation during this time. Many believed he was forgoing his only opportunity to be president; Republican Thomas E. Dewey was considered the other probable winner, would presumably serve two terms, and Eisenhower, at age 66 in 1956, would then be too old.
Why was it unlikely that Eisenhower would run for president in 1956?
Answer: too old


Question: METRO began light rail service on January 1, 2004, with the inaugural track ("Red Line") running about 8 miles (13 km) from the University of Houston–Downtown (UHD), which traverses through the Texas Medical Center and terminates at NRG Park. METRO is currently in the design phase of a 10-year expansion plan that will add five more lines. and expand the current Red Line. Amtrak, the national passenger rail system, provides service three times a week to Houston via the Sunset Limited (Los Angeles–New Orleans), which stops at a train station on the north side of the downtown area. The station saw 14,891 boardings and alightings in fiscal year 2008. In 2012, there was a 25 percent increase in ridership to 20,327 passengers embarking from the Houston Amtrak station.
Is there an answer to this question:  How wide was the first light rail line in Houston?

Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
The aircraft carrier dramatically changed naval combat in World War II, because air power was becoming a significant factor in warfare. The advent of aircraft as focal weapons was driven by the superior range, flexibility and effectiveness of carrier-launched aircraft. They had higher range and precision than naval guns, making them highly effective. The versatility of the carrier was demonstrated in November 1940 when HMS Illustrious launched a long-range strike on the Italian fleet at their base in Taranto, signalling the beginning of the effective and highly mobile aircraft strikes. This operation incapacitated three of the six battleships at a cost of two torpedo bombers. World War II in the Pacific Ocean involved clashes between aircraft carrier fleets. The 1941 Japanese surprise attack on Pearl Harbor was a clear illustration of the power projection capability afforded by a large force of modern carriers. Concentrating six carriers in a single unit turned naval history about, as no other nation had fielded anything comparable. However, the vulnerability of carriers compared to traditional battleships when forced into a gun-range encounter was quickly illustrated by the sinking of HMS Glorious by German battleships during the Norwegian campaign in 1940.
What was signalled in 1940 when HMS Illustrious launched an strike on an Italian fleet?
A:
the beginning of the effective and highly mobile aircraft strikes