Hi, RM,JH, einstein lol
amps = watts divided by voltage, so 600 watts is 50 amps@12volt
r=voltage divided by current, so 60 watt headlamp at 12volts uses 5 amps , resistance would be 2.4 ohms
If you know any two, you can work out the other two.
Resistance = voltage divided by current
voltage = current x resistance
current = voltage divided by resistance
watts = voltage x current
hope this helps
Will
ps E=MC squared