Which of the following is used to quench electrical arcs in circuit breakers?

In circuit breakers, oil is commonly used to quench electrical arcs. When a circuit is interrupted, an intense electrical arc can form due to the high voltage, which can continue conducting electricity if not extinguished effectively. Oil acts as a cooling and insulating medium, helping to absorb the energy of the arc and extinguishing it by dissipating heat and preventing the arc from sustaining itself.

Air, gas, and water can also be used in various types of circuit breakers, but they are not as effective as oil in certain applications, particularly in oil circuit breakers where the properties of the oil provide favorable conditions for arc quenching. Oil's high dielectric strength and ability to remove heat make it a preferred choice in traditional designs where high current and voltage levels are involved.