Tell your instructor or teacher
This is because of of the heating effect of a current. The glow is a result of current passing through the filament. The current experiences resistance as a result heat is generated. When resistance is at zero, there potential differences is not needed hence temperature generated will be at a constant.
If the scale reads 650N, then the mass of whoever it is standing on the scale is
(weight) / (gravity) = (650N) / (9.8 m/s²) = 66.3 kilograms .
It's not MY mass, even if I'm the one standing on the scale.
If I stand on a scale and it reads 650 N, the scale is broken.