Today I bought a "Silicon Power 4GB Micro SDHC Class 10 High Speed Memory Card". Is this compatible with Raspberry Pi Model B?
It must be compatible with it.
Generally, 4 GB SD card or above is recommended. 2GB also works most of the time.
As per Card type, Prescribed card type are: SD & SDHC
Regarding "class 10", there might not be any problem, as it means its performance(speed) is larger (10Mb/s) than lower versions. Hence it can perform everything which lower versions(class 2, 4, 6) could do.