Final answer:
To accurately determine the voltage used by both the lamp and the fan in a Snap circuit, additional data on the circuit configuration is necessary. However, if both devices are designed for 12V and are in a typical setup, the circuit would likely use the same 12V for both the lamp and the fan.
Step-by-step explanation:
To determine how much voltage is used by both the lamp and the fan in a Snap circuit, we would need additional information about how they are connected in the circuit (series or parallel) and the voltage requirements for each device. However, it is worth noting that if a lamp designed for 12V is used in conjunction with any other device in a typical circuit, the source voltage required by the circuit would still be 12V, unless additional series resistance changes the effective voltage across each device.
Given the information from the various examples provided, if a 12V battery is powering a lamp in a circuit, it's reasonable to assume that 12V is the voltage used across the lamp. One would also assume the same 12V would be available for the fan unless there is a resistor or any other component that could potentially divide the voltage.