A1.11 kg piece of aluminum at 78.3 c is put into a glass with 0.210 kg of water at 15.0 c. what is their final temperature?

M = mass of aluminium = 1.11 kg

= specific heat of aluminium = 900

= initial temperature of aluminium = 78.3 c

m = mass of water = 0.210 kg

= specific heat of water = 4186

= initial temperature of water = 15 c

T = final equilibrium temperature = ?

using conservation of heat

Heat lost by aluminium = heat gained by water

M ( - T) = m (T - )

(1.11) (900) (78.3 - T) = (0.210) (4186) (T - 15)

T = 48.7 c

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.