AP EAPCET 07-Jul-2022 Shift 1 Paper

As density, ρ∝

1

V

Where, V= volume
We have,

ρ2

ρ1

=

V1

V2

=

V1

V1(1+r∆θ)

r= coefficient of cubical expansion
∆θ= rise of temperature
Since, ρ2=ρ1(1−r∆θ)
Here, r=5×10−4‌∘C−1
∆θ=40∘C
So, in given case

ρ2

ρ1

=1−5×10−4×40
=1−2×10−2=0.08
Hence, fractional change in density =

∆ρ

ρ1

⇒

∆ρ

ρ1

=

ρ2−ρ1

ρ1

=

ρ2

ρ1

−1
⇒ Fractional change is

∆ρ

ρ1

=0.08−1=−0.02
Hence, negative sign shows decrease in density.