Thermal Properties of Matter - Result Question 3

3. The value of coefficient of volume expansion of glycerine is 5×104K1. The fractional change in the density of glycerine for a rise of 40C in its temperature, is:

[2015 RS]

(a) 0.020

(b) 0.025

(c) 0.010

(d) 0.015

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Answer:

Correct Answer: 3. (a)

Solution:

  1. (a) From question,

Rise in temperature Δt=40C

Coefficient of volume expansion

γ=5×104K1

Fractional change in the density Δρρ0=ρ0ρTρ0

ρT=ρ0(1γΔt)

Δρρ0=ρ0ρTρ0=γΔT=(5×104)(40)=0.020

Most substances (solid & liquid) expand when they are heated, so volume of a given mass of a substance increases on heating so density decreases as

ρ1Vρρ=VV=VV+ΔV=VV+γVAθ=11+γΔθ



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