# 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 × 10

^{5}Pa is pressure that is kept constant during expansion and ΔV is change in volumeΔV = V

_{i}β ΔTwhere V

_{i}= 10^{3}× 10^{-6}m^{3}is initial volume , β = 210 × 10^{-6}/°C is volume expansion coefficient and ΔT = 50 °C is change in temperature .ΔV = 10

^{3}× 10^{-6}× 210 × 10^{-6}× 50 = 1.05 × 10^{-5}m^{3}Workdone = P ΔV = 1.01 × 10

^{5}× 1.05 × 10^{-5}= 1.060 J-----------------------------------------------

Chane in internal energy ΔU = m C

_{p}ΔTwhere m is mass of water , C

_{p}is specific heat and ΔT is change in temperaturemass of water m = volume × density = 10

^{3}× 10^{-6}× 1000 = 1 kgChane in internal energy ΔU =1 × 4186