Elongation of 2 Test Specimens

No reason. Because your view may be incorrect.

Have no idea what yer on about....

More gauge?

Less Gauge?

explain a little

The Gauge length is as simple,the length of the test specimen. For the same material with same diameters and with different lengths the elongation of lengthier rod is larger than the smaller length rod, for the same load values.

I'll bet if one is twice as long as the other, it has twice as much elongation. Doesn't that give you a hint?

Please post photographs.

Because strain . . . wait, this sounds like a homework question. You know the rules.

Homework?

Maybe if you look up why a rubber band stretches you will have your answer. Your specimens a rubber band and a key ring. What are the properties that makes them different that could explain the elongation when a load is placed on them. You could also look at lifting devices like chains. What properties would two identical sized chains have different that would give them a different load rating?

Elongation is expressed as a percentage. The same percentage of a longer specimen equals a greater length of elongation. Duh.

anybody can tell the reason for difference in elongation in terms of material micro structure movements? Is the possibility of voids in the micro structure plays a role in this phenomenon or volume of material under load affects this or any other reason?

I understood that the concept of Strain has come to avoid the dependability of elongation with the length of the specimen and so the strain of the two different length specimen (same material & Same force applied) will be same.

Your original question has nothing to do with micro structure.

Tell us what the relationship between strain and elongation is. The answer to your original question will be obvious.

Strain is the elongation happened in unit length of test specimen (unit less). But elongation is the total deformation happened in specimen (unit mm)