When you pull out the plug connected to an electrical appliance, you often observe a spark. To which property of the appliance is this related ?

The spark observed when pulling out a plug is primarily due to the property of inductance. According to Faraday's Law of Induction, when the circuit is suddenly broken, the current drops rapidly to zero, causing a collapsing magnetic field [t1][t7]. This rapid change in magnetic flux induces a high 'back EMF' or 'inductive kickback' [t1][t3]. This induced voltage is often high enough to ionize the air between the plug and the socket, resulting in a visible spark or arc [t2][t4]. While resistance and wattage relate to the heating and power consumption of the appliance [c1][c3], they do not cause this specific electromagnetic discharge. Inductance is inherent in any appliance with coils or motors, such as fans or refrigerators, which store energy in their magnetic fields [t6][t7].

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 4: Electricity: Magnetic and Heating Effects > A step further > p. 54
2. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 4: Electricity: Magnetic and Heating Effects > Think like a scientist > p. 53