Answer to Question #107515 in Field Theory for Henry

Question

PHYSICS
1. A piece of copper block of mass 24g at 2300C is placed in a copper calorimeter of
mass 60g containing 54g of water at 31oC. Assuming heat losses are negligible,
calculate the final steady temperature of the mixture. [Specific hest capacity of water
= 4200Jkg – 1 K – 1
, specific heat capacity of copper = 400Jkg – 1 K – 1
].
2. The lower and upper fixed points marked on a mercury in glass thermometer are
210mm apart. The end of the mercury column in the tube is 49mm above the lower
fixed point in a room. What is the temperature of the room in degree celcius.

Answer 1

1)

Heat lost by the copper block = heat gained by water + heat gained by calorimeter

Let the equilibrium temperature be T

$0.024\times400\times(210-T)=0.06\times400\times(T-31)+0.054\times4200\times(T-31)$

$2016-9.6T=24T-744+226.8T-7030.8$

$260.4T=5758.8 \\T=22.12^oC$

2)

$210mm .... 100^oC\\ 49mm .... (\theta)\\ 0mm .... 0^oC\\ \frac{49 - 0}{210 - 0} =\frac{\theta - 0}{100 - 0} \\\frac{49}{210} = \frac{\theta}{100} \\ \theta = 23.3oC$