A thermally insulated, closed copper vessel contains water at `15^(0)C`. When the vessel is shaken vigorously for 15 minutes, the temprature rises to `17^(0)C`. The mass of the vessel is 100 g and that of the water is 200 g. the specific heat capacities of copper and water are `420 Jkg^(-1) K^(-1)` and `4200 J kg^(-1)K^(-1)` respectively. negalect any thermal expansion.
(a) how much heat is transferred to the liquid-vessel system ?
(b)how much work has been done on this system?
(c ) how much is the increase in internal energy if the system ?

Answer

A, B, C, D

Explanation

`t_1=15^@C,t_2=17^@C,`
`Deltat-t_2-t_1`
`=`17^@C-15^@C=2^@C=275 K`
`m_v=100g=0*1kg.,`
`m_w=200g=0*2kg`
` Sp.heat capacity of`
`c_u=420 J/kg-k`
`Sp.heat capacity of water `=4200 J /kg-k
(a) The heat transferred to the liquid vessel system is 0. The internal heat is shared in between the vessel and water.
(b) Work done on the system
= Heat product unit `
`rArr bw=100x10^-3x420x2+200`
`x10^--3x4200x2`
`=84+84x20=84x21`
`=1764 J`
` (c)`dQ=0,dU=-dW=1764`
` since `dw =-ve work done in the system