My meaning of Vemitter means 'voltage at the emitter', obviously.
Why don't you just do what everyone else does (most people who know anyway) and divide the desired collector current by the typical DC current gain (100) to calculate the required base current.
How much do the LEDs draw ?
As Raschemmel said, emitter is grounded, then "Vemitter" is 0V
For the common emitter configuration .... which is what the OP is using...and which is the usual configuration for connecting a load...the voltage at the emitter is zero Volt. For an emitter follower configuration, the emitter voltage will not be zero Volt.
Wawa recommends IB = C/30 which would be 400/30 = 13.3 mA base current.RB = (5V-1.5V)/0.0133 A = 263 (260) ohm.
In general, for small transistors like the 2N2222, the base current should be >= 1/20 of the collector current.
1:10 is used if you want to switch close to the transistor's maximum collector current.For lower currents, 1:20 should be enough.
Use ~1:20 for small transistors, ~1:10 for power transistors, and ~1:250 for darlingtons.
(OldSteve, where are you getting the ohm symbol from ?)
Just between you and me, from the Windows "Character Map". (A standard Windows accessory.)
Ω Ω Ω Ω Ω Ω(I'm glad that only took me 30 years to learn that...)
It's more like an OPEN COLLECTOR than COMMON EMITTER.Transistor Configurations
Learn your circuit configurations before coming to argue with me mate.
If you know your configurations then why are you referring to a Vemitter when it's 0V ?