Problem: The Paleozoic spanned from roughly 541 to 252 million years ago (Ma) and is subdivided into six geologic periods; from oldest to youngest they are the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian. Geologically, the Paleozoic starts shortly after the breakup of a supercontinent called Pannotia and at the end of a global ice age. Throughout the early Paleozoic, the Earth's landmass was broken up into a substantial number of relatively small continents. Toward the end of the era the continents gathered together into a supercontinent called Pangaea, which included most of the Earth's land area.
How many periods of geology are within the Paleozoic era?
The answer is the following: six

Problem: The manipulation of time at higher latitudes (for example Iceland, Nunavut or Alaska) has little impact on daily life, because the length of day and night changes more extremely throughout the seasons (in comparison to other latitudes), and thus sunrise and sunset times are significantly out of sync with standard working hours regardless of manipulations of the clock. DST is also of little use for locations near the equator, because these regions see only a small variation in daylight in the course of the year.
What region of the earth sees little change in daylight from season to season?
The answer is the following: near the equator

Problem: Though the iPod was released in 2001, its price and Mac-only compatibility caused sales to be relatively slow until 2004. The iPod line came from Apple's "digital hub" category, when the company began creating software for the growing market of personal digital devices. Digital cameras, camcorders and organizers had well-established mainstream markets, but the company found existing digital music players "big and clunky or small and useless" with user interfaces that were "unbelievably awful," so Apple decided to develop its own. As ordered by CEO Steve Jobs, Apple's hardware engineering chief Jon Rubinstein assembled a team of engineers to design the iPod line, including hardware engineers Tony Fadell and Michael Dhuey, and design engineer Sir Jonathan Ive. Rubinstein had already discovered the Toshiba disk drive when meeting with an Apple supplier in Japan, and purchased the rights to it for Apple, and had also already worked out how the screen, battery, and other key elements would work. The aesthetic was inspired by the 1958 Braun T3 transistor radio designed by Dieter Rams, while the wheel based user interface was prompted by Bang & Olufsen's BeoCom 6000 telephone. The product ("the Walkman of the twenty-first century" ) was developed in less than one year and unveiled on October 23, 2001. Jobs announced it as a Mac-compatible product with a 5 GB hard drive that put "1,000 songs in your pocket."
How large was the hard drive on the original iPod?
The answer is the following: 5 GB

Problem: BJTs have three terminals, corresponding to the three layers of semiconductor—an emitter, a base, and a collector. They are useful in amplifiers because the currents at the emitter and collector are controllable by a relatively small base current. In an n–p–n transistor operating in the active region, the emitter–base junction is forward biased (electrons and holes recombine at the junction), and electrons are injected into the base region. Because the base is narrow, most of these electrons will diffuse into the reverse-biased (electrons and holes are formed at, and move away from the junction) base–collector junction and be swept into the collector; perhaps one-hundredth of the electrons will recombine in the base, which is the dominant mechanism in the base current. By controlling the number of electrons that can leave the base, the number of electrons entering the collector can be controlled. Collector current is approximately β (common-emitter current gain) times the base current. It is typically greater than 100 for small-signal transistors but can be smaller in transistors designed for high-power applications.
How can one find the amount of collector current?
The answer is the following:
β (common-emitter current gain) times the base current