When someone exclaims "Eureka!", they are probably experiencing:

• When someone exclaims "Eureka!", they are probably experiencing: Excitement.

• Eureka! (exclamation/interjection)
English Meaning: A cry of joy, excitement, or satisfaction when one finds or discovers something.
Bangla Meaning: (গ্রিক = আমি পেয়েছি) ইউরেকা; কোনো আবিষ্কারের আনন্দচিত্কার।

• Example:
- The answer hit me. ‘Eureka!’ I cried.

Source:
1. Accessible Dictionary by Bangla Academy.
2. Oxford Learner's Dictionary.