JEE Main 2020PhysicsThermal Properties of MatterHardNumerical

JEE Main 2020 — Thermal Properties of Matter Question with Solution

JEE Main 2020 (08 Jan Shift 2)

Question

Three containers C1,C2 and C3 have water at different temperatures. The table below shows the final temperature T when different amounts of water (given in liters) are taken from each container and mixed (assume no loss of heat during the process)




































C1 C2 C3 T
1l 2l -- 60oC
-- 1l 2l 30oC
2l -- 1l 60oC
1l 1l 1l θ


The value of θ (in oC to the nearest integer) is___________

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Show full solutionCorrect answer: 50
Correct answer
50

Step-by-step explanation

Let θ1, θ2 and θ3 be the temperatures of water in three containers.

1θ1+2θ2+0θ3=1+260
θ1+2θ2=180 …. (1)
0×θ1+1×θ2+2×θ3=1+230
θ2+2θ3=90 …… (2)
2×θ1+0×θ2+1×θ3=2+160
2θ1+θ3=180 …. (3)
and θ1+θ2+θ3=1+1+1θ
from (1)+(2)+(3)
3θ1+3θ2+3θ3=450⟹θ1+θ2+θ3=150
from (4) equation 150=3θ⟹θ=50 °C

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About this question

This is a previous-year question from JEE Main 2020, covering the Thermal Properties of Matter chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.