At what voltage does air become a good conductor?

Air typically becomes a good conductor of electricity at high voltages due to its insulating properties at lower voltages. When the voltage in the air reaches a certain threshold, ionization occurs, allowing the air to start conducting. The correct answer, 10,000 volts, falls within the range at which air can ionize sufficiently to allow for the conduction of electricity. This phenomenon is commonly witnessed in electrical discharges such as lightning, which occur under conditions of very high voltage.

Lower voltages such as 120 volts and even 5,000 volts generally don't provide enough energy to ionize the air significantly, thus maintaining its insulative properties. Voltaic discharges and risks associated with electric arcs and other hazards are far more prevalent at or above the 10,000-volt threshold, emphasizing the significance of this voltage as a marker for when air becomes a good conductor.

Voltages over 50,000 volts can also result in air becoming a conductor, but the emphasis in this quiz is on the critical point of ionization beginning to occur, solidifying 10,000 volts as a more standardized reference point for air conductivity in practical applications.