how to convert lb into Gauss?

Cannot, the units are different.

for interchangable units, u have to divide the unit by a constant such as c, the light speed or h, the plank constant. it's the theoretical physicists' lazy way of keeping measurements. there are many constants in physics....all u have is to find them.

for example, the astronomers don't talk about distance in meters, but in light years...the distance light travels in a solar year.........

first, we have to find a relationship of mass to magnetic field and i have found such an equation in the reference source. (it only work if u can find a relationship and the unit conversion is only meaningful to that equation,.)

F=qE+q'(v X B).

or F/l=2i^2/c^2r

or F=2i^2l/c^2r

or mg=guass^2/c^2

or divide the weight, mg, which is charged by 1/c^2 to convert it to gauss^2.

in other words, u can't convert weight to guass, but to guass squared....

please read "fear of physics" by krauss or "gravitation" by misner, wheeler and thorne.

These are not the same units of measurement.