Subject: is induced emf a frame dependent quantity

We know that emf induced in a rod of 
length  'l' moving in a magnetic field  of 
magnitude 'B'   with speed 'v' 
perpendicular to field is given by E=v *b * 
l.
But what this speed is with respect to?  If 
'v' is the speed measured from some 
frame then the induced emf becomes a 
frame dependent quantity. So of I connect 
a bulb to the terminals of rod(which will 
behave as a battery) then the will be seen 
glowing in one frame but will be seen off 
in another frame moving with the same 
speed as that of rod in its direction.
If the answer is that 'in second frame the 
rod is at rest but the field is moving at the 
same speed v in opposite direction', then 
it introduces a concept of motion of field. 
Firstly, i m unaware of any such concept. 
Secondly, another question arises that 
will there be some added phenomenon if 
the field is observed from an accelerated 
frame (such as emission of some  energy)

Re: is induced emf a frame dependent quantity