Atest charge is a a very small negative charge with little miee b a point charge of q 100 c c a spbere of charge d. a very amall positive charge with little s

D. a very small positive charge with little s

Explanation:

A test charge is a very small charge with positive value which do not disturb the electric field exist in the region

So test charge is to find out the strength of electric field that exist in the region.

If the magnitude of test charge is large then it will change the strength of the existing electric field and due to this the value of the force will be altered.

So here in this case the test charge must be small as well as it must be positive nature

their crystal patterns have been disrupted by stress

pretty sure it's false