What is the difference between a spark and an arc?

Somesh,

What is your confusion? I have my doubts when a student can't find the answer to such a very basic question, especially if he were to search the internet on his own. If he did so he would find that the differences are in in energy level, time duration, intensity, gap, damage, etc.

Alan

Specifically saying Spark has discrete nature while arc has continuous nature...
For example, when there is loose connection at point of connection there will be sparking, and if you open high voltage isolator switch on onload,arc will be generated.

Hope you will get your confusion clear.

Thank you Mr Alan for such a thought provoking answer. All my confusion faded away as soon as you hit the discussion.

Mujeeb your example is confusing and it shows your confusion, both examples creates an arc my friend. a spark is created wherever there is a short.

I hope you will get your confusion clear.

Regards

Norman thank you for your correction and can you elaborate in detail...because I didn't get your point.
Thanks in advance

I think the difference is the same How about this," We experienced a voltage drop and all light bulbs were dime.' says a Technician. "Why " asked the in-charge. " the jumper on the neutral conductor had lose connection so when we arrived since it was dark,we sow sparks on the joint and we changed the connector since we could not tighten its bolt which was highly pitted due to continues arcing.( the spark has change to arc.......it is a question of semantic otherwise on Examination you have to clear the ambiguity and sound definite.
Good luck

Both a spark and arc are created when there is a breakdown of the air insulation and ionization takes place between two points. If the breakdown is short and the arc is extinguished it may be termed a spark, if the arc is maintained for some length of time it may be termed an arc. This time period in case of high voltage equipment may be of the order of milliseconds, but it is normally called an arc. The term sparking is usually used while describing lower voltage and energy level equipment.

Good example of ans Arc versus a spark.
A spark (or spark breakdown) is a brief event where an insulating medium (often air) is electrically stressed sufficiently to cause it to break down. Once this occurs, a conducting filamentary region of the insulating medium changes into a low impedance conductor. This event is usually accompanied by a sharp click or bang, since the mechanisms associated with the formation of the spark also creates a shockwave in the surrounding medium.

Once spark breakdown occurs, the voltage across the gap plummets, and current surges through the spark discharge. If the surrounding circuitry has a limited amount of stored energy (such as a charged capacitor), the spark is quickly extinguished afterwards. However, if the power supply can continuously supply sufficient current, the spark rapidly evolves into an arc and current continues to flow. The diameter of the arc channel is a complex function of the available current and maximum arc length scales roughly with available supply voltage. A spark is a transient event. An arc is a longer duration event that can often be treated as being in local thermal equilibrium (LTE). Note that you can also create an arc using a lower voltage source (typically 10's of volts) by briefly touching one electrode to the other and then separating them to form an arc, as in arc welding.