The missing word in the problem is 'half'. In a series circuit, when a load is connected, it causes a voltage drop across the internal series resistance (R) of the battery. This means that the output voltage of the battery decreases when the load is connected. In this case, the no-load output voltage of the battery is 12 volts, and when the load is connected, the voltage is effectively halved due to the internal resistance. This concept is crucial in understanding how batteries behave under load and the importance of internal resistance in circuit design.