Without specific information I cannot answer your question, however you can work it out.
For a dc or single phase system you need to know 2 simple laws. P=V x I & V=I x R
where:
P = power in watts
V = Voltage in Volts
I = Current in Amps
R=Resistance in Ohms
we can therefore derive that since I=V/R and P=V x I then P=V x V/R or vsquared over R
or in your case R = V(squared) / P = 12 x 12 / 30 = 144/30 = 4.8 ohms
Now use the formula supplied with your voltage value, and you will know what the resistance is .
See isn't math fun.
To calculate the resistance in ohms, you also need to know the voltage. The formula to find the resistance in ohms is R = V^2 / P, where R is the resistance in ohms, V is the voltage, and P is the power in watts.
The Kicker Impulse 352xi amp has a maximum power output of 35 watts per channel x 2 channels at 4 ohms or 35 watts x 2 channels at 2 ohms.
The Urei 6250 power amplifier has a power output of 250 watts per channel into 8 ohms.
The Sony XM752X amplifier can output up to 280 watts RMS per channel at 4 ohms, or 380 watts RMS per channel at 2 ohms, when both channels are driven with a 20Hz - 20kHz signal.
The power in watts is equal to the volts times the amps so that is 120 x 7.5.
75 x 1 Watts RMS @ 4 Ohms 150 x 1 Watts RMS @ 2 Ohms
Ohms can be found by using these formulas. Ohms = Volts/Amps, Ohms = (Volts (squared))/Watts, Ohms = Watts/(Amps (squared)).
To calculate the resistance in ohms, you also need to know the voltage. The formula to find the resistance in ohms is R = V^2 / P, where R is the resistance in ohms, V is the voltage, and P is the power in watts.
The normal calculations for watts are as follows.amps x volts = wattsvolts2 / ohms = wattsamps2 x ohms = wattsScroll down to the Related links and look at "Watts, Volts, Amperes, and Ohms".
Ignition 30 watts, fans 30 watts, driving lights 30 watts, headlights 100 watts. Total about 200 watts.
There are three formulas that you can use. Amps = Volts/Ohms Amps = Watts/Volts Amps = sq root of Watts/Ohms
The Kicker Impulse 352xi amp has a maximum power output of 35 watts per channel x 2 channels at 4 ohms or 35 watts x 2 channels at 2 ohms.
The Urei 6250 power amplifier has a power output of 250 watts per channel into 8 ohms.
The Sony XM752X amplifier can output up to 280 watts RMS per channel at 4 ohms, or 380 watts RMS per channel at 2 ohms, when both channels are driven with a 20Hz - 20kHz signal.
The power in watts is equal to the volts times the amps so that is 120 x 7.5.
The Orion CS 100.2 amp is rated for 100 watts RMS per channel at 2 ohms.
The wattage and ohms of a speaker are not related; the resistance for speakers is usually 4 or 8 ohms.