An object appears red when viewed with white light. What color would it appear when viewed with blue light?

Colour of any object is by the colour of light it reflects i.e if white light is incident on the object,it will reflect blue color.so it will appear blue.But if red light is incident on it,it will not reflect that and absorb it.so as it will not reflect any light it will appear black.

Explanation:

the higher the current the higher the mag field around it the higher the influence on the compass