30 g of water at `300^(@)C` is in a beaker . Which of the following when added to water , will have greater cooling effect ?( specific heat of copper =`0.1 cal//g^(@)C`)

Options

A. 100 g of water at `10^(@)C`
B. 15 g of water at `0^(@)C`
C. 3 g of ice at `0^(@)C`
D. 18 g of copper at `0^(@)C`

Answer

A

Explanation

(a) 100 g of water at `10^(@)C`
Total heat released `= m_(1)s_(1)Deltat_(1) + m_(2)s_(2)Deltat_(2)`
`=[(30) ( 300+ (100)(10)]417.9`
`= 417.9 xx 10^(4) cal`
`(b) Q = [(30)(417.9)(300) + (15)(417.9)(0)] = 376.1 xx 10^(4) cal`
( c )` Q = [(30)(417.9)(300) + (3) (203)(0)] = 376.1 xx 10^(4) cal`
( d )` Q = [(30)(417.9)(300) + (18 ) (0.1) (0) = 376.1 xx 10^(4) cal`
` therefore` 100 g of water at `10^(@)C` produce more cooling effect.