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1 Physics -- First Law of Thermodynamics

Water falls from 350 high, find the temperature change assuming that the whole of energy due to fallconverted into heat. Swater = 4200JkgC-1 

Water falls from 350 high, find the temperature change assuming that the whole of energy due to fall

converted into heat. Swater = 4200JkgC-1 

1 Answers

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Solution:

Given,

height of water (h) = 350 m

mass of water (m) = ?

Let acceleration due to gravity be g = 10 m/s^2

Then, the potential energy of water at height h (PE) = mgh

= m (10) (350)

= (3500 m) Joules

Again, the amount of heat energy gained by water is given by (Q) = ms 'dt' where s is the specific heat capacity of water and 'dt' is the difference in temperature.

Question says that the entire PE is converted to Q so,

PE = Q

or, 3500 m = ms 'dt'

or, 3500 = 4200 'dt'

So, 'dt' = 3500/4200 = 5/6 K

Hence, the change in temperature is 5/6 K.

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