Current Questions

I'm planning on starting my first major mod soon but have some questions.
My plan is to mount a K2 on an UHS in a 4 cell M@g I want to run it at 1500ma for max output. I see that the K2 long throw utilizes 4 NiMH cells at 1.2V each with a resistor to maintain 7.2 Watts. If i were to use alkalines I would be at 6V at least initially so would I only need 1.2A to reach 7.2 Watts ? Also are resistors inefficient do they waste energy via heat? What are the advantages/disadvantages of using a buck circuit to limit current ? I swear I'm almost done asking questions but how to I get constant output using alkalines?

As you suspected it, resistors lose energy by radiating heat. This doesn't mean they are ineficient, it all depends on how you define ineficient.

Any component with a resistive value (condenser, coils etc) radiate heat.

Thanks for the info. Are regulating circuits more efficient?