CBSE Class 11-science Answered
Heat is added to 10^3 cubic cm of water at atmospheric pressure. The water's temperature increases by 50 degrees celsius. Find (a) the work done by the water as it expands (b) the increase in water's internal energy.
Asked by arjunsah797 | 01 Mar, 2022, 03:01: PM
Expert Answer
Workdone = P ΔV
where P = 1.01 × 105 Pa is pressure that is kept constant during expansion and ΔV is change in volume
ΔV = Vi β ΔT
where Vi = 103 × 10-6 m3 is initial volume , β = 210 × 10-6 /°C is volume expansion coefficient and ΔT = 50 °C is change in temperature .
ΔV = 103 × 10-6 × 210 × 10-6 × 50 = 1.05 × 10-5 m3
Workdone = P ΔV = 1.01 × 105 × 1.05 × 10-5 = 1.060 J
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Chane in internal energy ΔU = m Cp ΔT
where m is mass of water , Cp is specific heat and ΔT is change in temperature
mass of water m = volume × density = 103 × 10-6 × 1000 = 1 kg
Chane in internal energy ΔU =1 × 4186