If you were taking a college course called iPhone 101, your professor might identify three factors that have made Apple’s smartphone a mega-success.

First, design. A single company, known for its obsession over details, produces both the hardware and the software. The result is a single, coherently designed whole.

Second, superior components. As the world’s largest tech company, Apple can call the shots with its part suppliers. It can often incorporate new technologies — scratch-resistant Gorilla glass, say, or the supersharp Retina screen — before its rivals can.

Third, compatibility. The iPhone’s ubiquity has led to a universe of accessories that fit it. Walk into a hotel room, and there’s probably an iPhone connector built into the alarm clock.

If you had to write a term paper for this course, you might open with this argument: that in creating the new iPhone 5 ($200 with contract), Apple strengthened its first two advantages — but handed its rivals the third one on a silver platter.

Let’s start with design. The new phone, in all black or white, is beautiful. Especially the black one, whose gleaming, black-on-black, glass-and-aluminum body carries the design cues of a Stealth bomber. The rumors ran rampant that the iPhone 5 would have a larger screen. Would it be huge, like many Android phones? Those giant screens are thudding slabs in your pocket, but they’re fantastic for maps, books, Web sites, photos and movies.

As it turns out, the new iPhone’s updated footprint (handprint?) is nothing like the Imax size of its rivals. It’s the same 2.3 inches wide, but its screen has grown taller by half an inch — 176 very tiny pixels.

It’s a nice but not life-changing change. You gain an extra row of icons on the Home screen, more messages in e-mail lists, wider keyboard keys in landscape mode and a more expansive view of all the other built-in apps. (Non-Apple apps can be written to exploit the bigger screen. Until then, they sit in the center of the larger screen, flanked by unnoticeable slim black bars.)

At 0.3 inch, the phone is thinner than before, startlingly so — the thinnest in the world, Apple says. It’s also lighter, just under four ounces; it disappears completely in your pocket. This iPhone is so light, tall and flat, it’s well on its way to becoming a bookmark.

Second advantage: components. There’s no breakthrough feature this time, no Retina screen or Siri. (Thought recognition will have to wait for the iPhone 13.)

Even so, nearly every feature has been upgraded, with a focus on what counts: screen, sound, camera, speed.

The iPhone 5 is now a 4G LTE phone, meaning that in certain lucky cities, you get wicked-fast Internet connections. (Verizon has by far the most LTE cities, with AT&T a distant second and Sprint at the rear. Here’s a cool coverage comparison map: j.mp/V5wEwN.)

The phone itself runs faster, too. Its new processor runs twice as fast, says Apple. Few people complained about the old phone’s speed, but this one certainly zips.

The screen now has better color reproduction. The front-facing camera captures high-definition video now (720p). The battery offers the same talk time as before (eight hours), but adds two more hours of Web browsing (eight hours), even on LTE networks. In practical terms, you encounter fewer days when the battery dies by dinnertime — a frequent occurrence with 4G phones.

The camera is among the best ever put into a phone. Its lowlight shots blow away the same efforts from an iPhone 4S. Its shot-to-shot times have been improved by 40 percent. And you can take stills even while recording video (1080p hi-def, of course).