So each bulb is releasing 24 joules of light energy per second.
In a series circuit, all the current flows through each bulb. The voltage of the current flowing through the series circuit will decrease from 12 volt to 0 volt. Since each bulb has the same resistance, the voltage will decrease 6 volts as the current passes through each bulb.
Voltage decrease = Current * Resistance
6 = Current * 6 ohms
Current = 1 amp
So the current flowing through each bulb = 1 amp. Since the bulbs are in series, this 1 amp of current flows through each bulb.
Power for each bulb = 6 volts * 1 amp = 6 watts
1 watt = 1 joule of energy per second
So each bulb is releasing 6 joules of light energy per second.
In the parallel circuit, more current was flowing, because there are 2 equal resistance paths for the current to flow through. Since the resistance of each path is the same, the amount of current flowing through each path is the same. But the total current is the sum of the currents in each path. So the parallel circuit has 2 factors making the light bulbs shine brighter. Higher current and maximum voltage.
High current * high voltage = High power = BRIGHT BULBS
In a series circuit, the total resistance is the sum of the resistance of the 2 bulbs. Since the total resistance is higher, the total current is lower. The current time the resistance = the decrease of voltage. The decrease of voltage determines the amount of energy the electrons are carrying to the bulb. Less energy per electron and less electrons per second = less energy per second.
So the series circuit has 2 factors making the light bulbs shine dimmer. Lower current and lower voltage.
Low current low voltage = low power = DIM BULBS