Change in length of the metal wire (Δl) when its temperature is changed by ΔT is given by Δl=lαΔT Here, α= Coefficient of linear expansion Here, Δl=0.02%,ΔT=10°C ∴α=
Δl
lΔT
=
0.02
100×10
⇒α=2×10−5 Volume coefficient of expansion, γ=3α=6×10−5 ∵ρ=
M
V
ΔV
V
×100=γΔT=(6×10−5×10×100)=6×10−2 Volume increase by 0.06% therefore density decrease by 0.06%.