Problem: Transistor:

Discrete transistors are individually packaged transistors. Transistors come in many different semiconductor packages (see image). The two main categories are through-hole (or leaded), and surface-mount, also known as surface-mount device (SMD). The ball grid array (BGA) is the latest surface-mount package (currently only for large integrated circuits). It has solder "balls" on the underside in place of leads. Because they are smaller and have shorter interconnections, SMDs have better high-frequency characteristics but lower power rating.

What is a ball grid array composed of?
---
A: solder "balls" on the underside in place of leads

Problem: Elevator:

Direction lanterns are also found both inside and outside elevator cars, but they should always be visible from outside because their primary purpose is to help people decide whether or not to get on the elevator. If somebody waiting for the elevator wants to go up, but a car comes first that indicates that it is going down, then the person may decide not to get on the elevator. If the person waits, then one will still stop going up. Direction indicators are sometimes etched with arrows or shaped like arrows and/or use the convention that one that lights up red means "down" and green means "up". Since the color convention is often undermined or overridden by systems that do not invoke it, it is usually used only in conjunction with other differentiating factors. An example of a place whose elevators use only the color convention to differentiate between directions is the Museum of Contemporary Art in Chicago, where a single circle can be made to light up green for "up" and red for "down". Sometimes directions must be inferred by the position of the indicators relative to one another.

Some elevators may use the color convention for only what purpose?
---
A: to differentiate between directions

Problem: Comcast:

In 2004 and 2007, the American Customer Satisfaction Index (ACSI) survey found that Comcast had the worst customer satisfaction rating of any company or government agency in the country, including the Internal Revenue Service. The ACSI indicates that almost half of all cable customers (regardless of company) have registered complaints, and that cable is the only industry to score below 60 in the ACSI. Comcast's Customer Service Rating by the ACSI surveys indicate that the company's customer service has not improved since the surveys began in 2001. Analysis of the surveys states that "Comcast is one of the lowest scoring companies in ACSI. As its customer satisfaction eroded by 7% over the past year, revenue increased by 12%." The ACSI analysis also addresses this contradiction, stating that "Such pricing power usually comes with some level of monopoly protection and most cable companies have little competition at the local level. This also means that a cable company can do well financially even though its customers are not particularly satisfied."

Who listed the IRS as the company with the worst customer service rating?
---
A: unanswerable

Problem: Incandescent light bulb:

In 1906, the tungsten filament was introduced. Tungsten metal was initially not available in a form that allowed it to be drawn into fine wires. Filaments made from sintered tungsten powder were quite fragile. By 1910, a process was developed by William D. Coolidge at General Electric for production of a ductile form of tungsten. The process required pressing tungsten powder into bars, then several steps of sintering, swaging, and then wire drawing. It was found that very pure tungsten formed filaments that sagged in use, and that a very small "doping" treatment with potassium, silicon, and aluminium oxides at the level of a few hundred parts per million greatly improved the life and durability of the tungsten filaments.

What other materials were combined with tungsten?
---
A:
potassium, silicon, and aluminium oxides