The Raspberry Pi 2 Model B is the second generation Raspberry Pi. It replaced the original Raspberry Pi 1 Model B+ in February 2015. Compared to the Raspberry Pi 1 it has:
A 900MHz quad-core ARM Cortex-A7 CPU
Like the (Pi 1) Model B+, it also has:
4 USB ports
40 GPIO pins
Full HDMI port
Combined 3.5mm(0.14") audio jack and composite video
Camera interface (CSI)
Display interface (DSI)
Micro SD card slot
VideoCore IV 3D graphics core
Because it has an ARMv7 processor, it can run the full range of ARM GNU/Linux distributions, including Snappy Ubuntu Core, as well as Microsoft Windows 10.
The Raspberry Pi 2 has an identical form factor to the previous (Pi 1) Model B+ and has complete compatibility with Raspberry Pi 1.
We recommend the Raspberry Pi 2 Model B for use in schools: it offers more flexibility for learners than the leaner (Pi 1) Model A+, which is more useful for embedded projects and projects which require very low power.
Broadcom BCM2836 900MHz quad-core ARM Cortex-A7 CPU
1GB LPDDR2 SDRAM
4 x USB2.0 Ports
Video Out via full size HDMI, 3.5mm(0.14") A/V Jack or Raw LCD (DSI) interface
Audio Out via 3.5mm(0.14") A/V Jack or Audio over HDMI