Underscoring the tablet's importance to Apple, CEO Steve Jobs briefly emerged from a medical leave on March 2 and made a surprising appearance to unveil the iPad 2 himself.

Apple is back with a second-generation tablet computer that squeezes more power into a thinner shell while keeping prices in check. Underscoring the tablet’s importance to Apple, CEO Steve Jobs briefly emerged from a medical leave on March 2 and made a surprising appearance to unveil the iPad 2 himself.

With the original iPad, Apple proved there is great demand for a tablet that’s less than a laptop and more than a smart phone, yet performs many of the same tasks. Dozens of copycat touch-screen devices are in the works, but so far none has broken into the mainstream consciousness the way the iPad has.

“The competition is essentially going to be picking up the crumbs that Apple decides to leave behind,” said Ashok Kumar, an analyst with Rodman & Renshaw.

He said the number of software applications—or “apps”—available for the iPad gives Apple a huge advantage.

Sarah Rotman Epps, a Forrester Research analyst, said iPads should make up at least 20 million of the 24.1 million tablet computers she expects people in the U.S. to buy this year.

Except for Jobs’ appearance, little about the iPad 2 came as a surprise after months of speculation about features and upgrades. The tablet has two cameras built in for taking photos, recording video, and video chatting. The battery life will be the same as the original—about 10 hours of usage or a month on standby.

The iPad 2 is faster than its predecessor. Ross Rubin, an analyst for the market researchers NPD Group, said that should make the iPad better for creating music, video, and other content, rather than just consuming it.

The iPad 2 is also thinner—8.8 millimeters, or about a third of an inch, instead of the current 13.4 millimeters. It weighs just a bit less—1.3 pounds, compared with the original 1.5 pounds.

With a $39 accessory, people can connect the tablet to televisions, so they can watch high-definition videos on the bigger screen.

The next-generation iPads will cost the same as the originals—$499 to $829, depending on storage space and whether they can connect to the internet over a cellular network. Apple will add a white model to the current black. In the U.S., the iPad 2 will go on sale March 11 and work on AT&T Inc. and Verizon Wireless.

Apple’s online store began selling the original models for $100 off, starting at $399. Refurbished versions were even lower, starting at $349.

A reporter who used a white iPad 2 immediately after the announcement found it noticeably thinner, with a more rounded back. YouTube video loaded quickly using AT&T’s data service, and “Toy Story 3” played smoothly. Given its size, the iPad 2 appeared impractical for taking lots of photos, but both cameras will help with video chats—the front one to show the caller, and the back one to show what the caller is seeing.