NTA Abhyas JEE Main2020PhysicsThermal Properties of MatterPractice
Two identical beakers A and B contain equal volumes of two different liquids at 60 ° C each and left to cool down. Liquid in A has density of 8 × 10 2 k g m - 3 and specific heat of 2000 J k g - 1 K - 1 while the liquid in B has density 10 3 k g m - 3 and specific heat of 4000 J k g - 1 K - 1 . Which of the following best describes their temperature versus time graph schematically? (assume the emissivity of both the
Correct answer
1
Step-by-step solution
From Newton's law of cooling, Rate of cooling: - d T d t = 4 σ e A T 0 3 T - T 0 m s ∴ ρ A < ρ B m A < m B And s A < s B m A s A < m B s B At t = 0 , - d T d t A > - d T d t B Initially, the rate of cooling for A will be higher than B and temperature ( T ) vs time ( t ) graph will be a curve.