Vee erisoojus

Ülesanne. Kui palju energiat kulub_{$20 space l$}ämbritäie_{$10 space degree C$}kaevuvee soojendamiseks keemistemperatuurini?

Lahendus. Paneme kirja andmed.

Antud:
$V equals 20 space l equals space 2 times 10 to the power of negative 2 end exponent space m cubed T subscript 1 equals 10 space degree C T subscript 2 equals 100 space degree C c equals 4 comma 2 space fraction numerator k J over denominator k g times K end fraction rho equals 10 cubed space fraction numerator k g over denominator m cubed end fraction minus negative negative negative negative negative negative negative negative negative negative negative Q equals ?$

Andmetesse oleme lisanud vee keemistemperatuuri_{$T subscript 2 comma$} vee erisoojuse_$c$ning vee tiheduse _$rho.$Meid huvitav soojushulk avaldub

$Q equals c times left parenthesis T subscript 2 minus T subscript 1 right parenthesis times rho times V.$

Asendame valemisse eeltoodud andmed ning arvutame:

$Q equals 4 comma 2 space fraction numerator k J over denominator k g times K end fraction times left parenthesis 100 minus 10 right parenthesis space K times 10 cubed space fraction numerator k g over denominator m cubed end fraction times 2 times 10 to the power of negative 2 end exponent space m cubed equals 7 comma 6 times 10 to the power of 3 space end exponent k J.$

Mainime, et arvutuse tarvis polnud vaja temperatuure eraldi Kelvini skaalasse teisendada, sest oluline on temperatuuride vahe.

VASTUS: vee soojendamiseks kulub_{$7 comma 6 space M J$}energiat.