o heatwaterfrom 20∘ Cto boiling-point,an amountof
heat equal to 80kcal must be imparted to each kilogramme of
=
water) i.e. work of 80 X 427 34,160 kg must be done. The
Dneper hydroelectric station cannot do'this amount' of work,
since 1kg ofwaterwouldacquire theenergyneededfor this only
ifit fellfrom a heightofmorethan 34km,