If Avogadro Number $(NA)$ is changed than mass of $1 mol\;( 6.022 \times 10^{20}$ atom) of carbon. $=\frac{12 \times 6.022 \times 10^{20}}{6.022 \times 10^{23}}=12 \times 10^{-3} g$
Therefore the mass of $1 \;mol$ of carbon is changed
[આણ્વિય વજન : ${H}=1.008 ; {C}=12.00 ; {O}=16.00$ ]