Questions seem to be two! First is the direct current in a circuit with 12 V battery and 3 ohm resistor in it. The answer is 4 ampere if there is negligible internal resistance in the battery.
By ohm's law V = R I So, I = V/R
Second one is the alternating current with 120V given to 60 W bulb. The answer is 0.5 ampere. This 0.5 is the rms value of alternating current.
Power P = V I So, I = P/V
If the resistor is the only component across the battery terminals, then 4 amperes
of current will flow through the resistor, and the resistor will dissipate 48 watts,
until the battery runs out or the resistor explodes, whichever comes first.
The equation that you should use is I = W/E, Amps = Watts/Volts.
I = E/R = 120/25 = 4.8 amperes
You know if current is flowing in a bulb circuit because, if there is enough power (voltage times current), the bulb will illuminate. If there is current, but not enough power to illuminate the bulb, you will need to measure the current with an ammeter to see if there is any current.
The voltage of a circuit with a resistance of 250 ohms and a current of 0.95 amps is 237.5 volts. Ohms's law: Voltage = Current times Resistance
For a series circuit... Each bulb has different impedance (ohms) resulting in a different voltage drop across each. Remember Kirchoff's Current Law: The current at each point in a series circuit is the same. That same current, multiplied by the different voltage drops results in different powers (watts = amps * volts) for each bulb. For a parallel circuit. Again, each bulb still has different impedance. This time, the voltage drop is the same (Kirchoff's Voltage Law) but the current in each bulb is different. Same situation - different power in each bulb.
No. Circuit is open but still HOT.
I = E/R = 120/25 = 4.8 amperes
Current or amperage, is wattage divided by voltage. 60 / 120 = .5 amp.
Current or amperage, is wattage divided by voltage. 60 / 120 = .5 amp.
Current or amperage, is wattage divided by voltage. 60 / 120 = .5 amp.
Power = (voltage) x (current) 60 = 120 x I I = 60/120 = 1/2 Amp.
Current in a series circuit is the same throughout the circuit. Voltages are additive. Voltage in a parallel circuit is the same throughout the circuit. Currents are additive.
Incomplete circuit
You know if current is flowing in a bulb circuit because, if there is enough power (voltage times current), the bulb will illuminate. If there is current, but not enough power to illuminate the bulb, you will need to measure the current with an ammeter to see if there is any current.
No, the wattage is determined by the resistance of the filament in the light bulb. The formula to determine the wattage is Watts = Voltage (squared)/Resistance in Ohms. To find the resistance of a 120 volt light bulb use the formula, Resistance in Ohms = Voltage (squared)/Watts. So for a 100 watt bulb at 120 volts the resistance is 120 volts x 120 volts = 14400/100 = 144 ohms. For a 60 watt bulb at 120 volts the resistance is 120 volts x 120 volts = 14400/60 = 240 ohms. As you can see this holds true to Ohm's law, current is inversely proportional to the resistance of the circuit. The higher the resistance of a load, the harder it is for the current to flow. In this case less current results in less light being emitted from the filament in the light bulb.
A 60 watt bulb at 12 volts will pull 5 amps of current.
The voltage of a circuit with a resistance of 250 ohms and a current of 0.95 amps is 237.5 volts. Ohms's law: Voltage = Current times Resistance
No. Circuit is open but still HOT.