Based on the amperian loop question in the image, which current should be taken as positive as per sign convention?

Is it necessary to consider the sense of the loop or just take upward current as positive and downward as negative?

Can the sum of two equal vectors be equal to either vector

 

A nucleus X¹⁸⁴ at rest emitt alpha particle With kinetic energy 9.0MeV. The product Nucleus is Y. The values of Binding energy per nucleon of alpha particle & Y differ by 1.5MeV. The values of Binding energy per nucleon of X & Y differ by (n÷230) MeV, then n is

SUBJECT: PROBLEM BASED ON LINE DETECTION.
Query: How to apply all the filters for line detection on the following piece of image (provided below)? Explain its Observations to comment on its results.