Question

In a waterfall, water falls 60 m. Assume all the potential energy change increases its enthalpy (or internal energy, in this case they change by the same amount because this is an incompressible liquid). The specific heat capacity for water is 4184 J/kg·°C. Calculate the temperature rise of the water in °C. (8 points)

Answer 1

Answer:

The  temperature rise of the water is = 0.14 °c

Explanation:

Height = 60 m

Potential energy change ΔP = $m gh$

ΔP =  m × 9.81 × 60

ΔP = (588.6 × m) Joule

Since the Potential energy change is equal to the internal energy change or Enthalpy change.

ΔP = ΔH

Since  ΔH = m × C × ΔT

⇒ ΔP = m × C × ΔT

Put all the values in above formula we get

⇒ 588.6 × m = m × 4184 × ΔT

⇒ ΔT= 0.14 °c

Therefore the  temperature rise of the water is = 0.14 °c